Transfection complexes and methods of using the same

ABSTRACT

Disclosed herein are transfection complexes comprising at least one cell surface ligand; at least one helper lipid component; and a transfection enhancer. Also disclosed are pharmaceutical compositions comprising the disclosed transfection complexes, and a pharmaceutically acceptable carrier. Further, disclosed are methods of transfecting a cell, the method comprising the steps of: obtaining a transfection complex as disclosed; and contacting a cell with the transfection complex.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to the U.S. Provisional Application Ser. No. 62/211,675, filed on Aug. 28, 2015, the entire disclosure of both which is incorporated herein by reference, including all the drawings.

FIELD OF THE INVENTION

The present invention is in the field of transfection complexes suitable for the delivery of one or more biologically active agents to a cell and methods and kits for using the same.

BACKGROUND OF THE DISCLOSURE

Lipid aggregates such as liposomes or cationic polymers can facilitate introduction of macromolecules, such as DNA, RNA, and proteins, into living cells. Aggregates comprising cationic lipid components can be used to effect delivery of large anionic molecules, such as nucleic acids, into certain types of cells.

The use of cationic lipids has become increasingly popular since their introduction over 25 years ago. Several cationic lipids have been described in the literature and some of these are commercially available. DOTMA (N-[1-(2,3-dioleyloxy)propyl]-N,N,N-trimethylammonium chloride; IUPAC: 1,2-di-O-octadecenyl-3-trimethyl-ammonium propane (chloride salt); CAS Number: 104872-42-6) was the first cationic lipid to be synthesized for the purpose of nucleic acid transfection. DOTMA can be formulated alone or can be combined with DOPE (dioleoylphosphatidylethanolamine) into a liposome, and such liposomes can be used to deliver plasmids into some cells. Other classes of lipids subsequently have been synthesized by various groups. For example, DOGS (5-carboxyspermylglycinedioctadecylamide) was the first polycationic lipid to be prepared and other polycationic lipids have since been prepared. The lipid DOSPA (2,3-dioleyloxy-N-[2(spermine-carboxamido)ethyl]-N,N-dimethyl-1-propanaminium) has been described as an effective delivery agent.

In other examples, cholesterol-based cationic lipids, such as DC-Chol (N,N-dimethyl-N-ethylcarboxamidocholesterol) have been prepared and used for transfection. Also, 1,4-bis(3-N-oleylamino-propyl)piperazine was prepared and combined with histone H1 to generate a delivery reagent that was reported to be less toxic than other reagents. Some examples of commercially available lipids include Lipofectin® (DOTMA:DOPE) (Thermo-Fisher, Carlsbad, Calif.), LipofectAmine™ (DOSPA:DOPE) (Thermo-Fisher), LipofectAmine2000™ (Thermo-Fisher), Lipofectamine 3000 (Therom-Fisher), Fugene®, Transfectam® (DOGS), ViaFect (Promega), DNA-In, GeneIn (MTI-GlobalStem) Effectene®, and DC-Chol. Further examples are PEI polymers and dendrimers such as jetPEI (PolyPlus), and Superfect (Qiagen). None of these reagents can be used universally for all cells. This is perhaps not surprising in light of the variation in composition of the membranes of different types of cells as well as the barriers that can restrict entry of extracellular material into cells. Moreover, the mechanism by which cationic lipids deliver nucleic acids into cells is not clearly understood. The reagents are less efficient than viral delivery methods and are toxic to cells, although the degree of toxicity varies from reagent to reagent.

However, transfection agents, including cationic lipids, anionic lipids and cationic polymers, are not universally effective in all cell types. Effectiveness of transfection of different cells depends on the particular transfection agent composition. In general, polycationic lipids are more efficient than monocationic lipids in transfecting eukaryotic cells. In many cases, cationic lipids alone are not effective or are only partially effective for transfection so helper lipids or transfection enhancers can be used in combination with cationic lipids.

Many biological materials are taken up by cells via receptor-mediated endocytosis, in which a surface ligand binds to a cell-surface receptor, leading to clustering of ligand-bound receptors, and formation of coated pits followed by internalization of the ligands into endosomes. Both enveloped viruses, like influenza virus and alphaviruses, and non-enveloped viruses, like Adenovirus, infect cells via endocytotic mechanisms. Enhancement of dendrimer-mediated transfection of some cells by chloroquine (a lysosomotropic agent) suggests that endocytosis is involved in at least some transfections.

Introduction of foreign DNA sequences into eukaryotic cells mediated by viral infection is generally orders of magnitude more efficient than transfection with anionic lipids, cationic lipid, PEI, peptides, or dendrimer transfection agents. Viral infection of all the cells in a culture requires fewer than 10 virus particles per cell. Although the detailed mechanism of fusion is not fully understood and varies among viruses, viral fusion typically involves specific fusogenic agents, such as viral proteins, viral spike glycoproteins and peptides of viral spike glycoproteins. Cell binding and internalization also can be enhanced, accelerated or made selective with peptides that bind cell receptors. For example, the penton-base protein of the Adenovirus coat contains the peptide motif RGD (Arg-Gly-Asp) which mediates virus binding to integrins and viral internalization via receptor-mediated endocytosis.

The efficiency of cationic lipid transfections has been shown to be enhanced by the addition of whole virus particles to the transfection mixture. Certain viral components may also enhance the efficiency of cationic lipid-mediated transfection. For example, it has been suggested that “Lipofectin™”-mediated transfections may be enhanced 3-4-fold by adding influenza virus hemagglutinin peptides to the transfection mixture. Antibodies have been shown to enhance cationic lipid transfections and transferrin-poly lysine or asialoglycoprotein polylysine have been shown to enhance cationic lipid transfection.

Nevertheless, these methods do not work for all cell types, require relatively complex protocols and are inconvenient. It is apparent, therefore, that new and improved methods for introducing macromolecules, and particularly nucleic acids, into cell, are greatly to be desired. In particular, improved methods for introducing nucleic acids into a wider variety of cells, and particularly into primary cells, are greatly to be desired.

SUMMARY OF THE INVENTION

Disclosed herein are transfection complexes comprising at least one cell surface ligand; at least one helper lipid component; and a transfection enhancer. Also disclosed are pharmaceutical compositions comprising the disclosed transfection complexes, and a pharmaceutically acceptable carrier. Further, disclosed are methods of transfecting a cell, the method comprising the steps of: obtaining a transfection complex as disclosed; and contacting a cell with the transfection complex.

DETAILED DESCRIPTION OF THE EMBODIMENTS Definitions and Abbreviations

It is to be understood that the present invention is not limited to particular devices or biological systems, which may, of course, vary. It is also to be understood that, as used in this specification and the appended claims, the singular forms “a”, “an”, and “the” include singular and plural referents unless the content clearly dictates otherwise. Thus, for example, reference to “a lipid” includes one or more lipids. It is to be yet further understood that any terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.

Unless stated otherwise, the following terms, definitions, and abbreviations as used herein are intended to have the following meanings:

As used herein, the term “labeled” is intended to mean that a compound has at least one element, isotope, or chemical compound attached to enable the detection of the compound by using a radioactive or heavy isotope label, or an immune label such as an antibody or antigen or a label derived from a colored, luminescent, phosphorescent, or fluorescent dye. Photoaffinity labeling employing, for example, o-, m- and p-azidobenzoyls, substituted with one or more halogen moieties, including, but not limited to 4-azido-2,3,5,6-tetrafluorobenzoic acid, is utilized for the direct elucidation of intermolecular interactions in biological systems.

The terms “subject” and “animal” are synonymous and, as used herein, refer to humans as well as non-human animals, including, for example, mammals (e.g., a rodent, a mouse, a rat, a rabbit, a monkey, a dog, a cat, a primate, or a pig), birds, reptiles, amphibians, and fish.

The term “cell” generally refers to eukaryotic cells of any type and from any source. Types of eukaryotic cells include epithelial, fibroblastic, neuronal, hematopoietic cells and the like from primary cells, tumor cells or immortalized cell lines. Sources of such cells include any animal such as human, canine, mouse, hamster, cat, bovine, porcine, monkey, ape, sheep, fish, insect, fungus, and any plant including crop plants, algae, ornamentals and trees.

“Delivery” is used to denote a process by which a desired compound is transferred to a target cell such that the desired compound is ultimately located inside the target cell or in, or on, the target cell membrane. In many uses of the compounds of the invention, the desired compound is not readily taken up by the target cell and delivery via lipid aggregates or transfection complexes a means for delivering the desired compound to the appropriate cellular compartment within a cell. In certain uses, especially under in vivo conditions, delivery to a specific target cell type is preferable and can be facilitated by transfection complexes comprising surface ligands of the invention.

Drug refers to any therapeutic or prophylactic agent other than food which is used in the prevention, diagnosis, alleviation, treatment, or cure of disease in man or animal.

“Kit” refers to transfection or protein expression kits which include one or more of the compounds of the present invention or mixtures thereof. Such kits may comprise a carrying means being compartmentalized to receive in close confinement one or more container means such as vials, test tubes and the like. Each of such container means comprises components or a mixture of components needed to perform transfection. Such kits may include one or more components selected from nucleic acids (preferably one or more vectors), cells, one or more compounds of the present invention, lipid-aggregate forming compounds, transfection enhancers, biologically active substances, etc.

The term “associated with”, when used in the context of molecular interactions, refers to two entities linked by a direct or indirect covalent or non-covalent interaction, such as hydrogen bonding, van der Waals interactions, hydrophobic interactions, magnetic interactions, electrostatic interactions, etc.

The term “biocompatible,” as used herein refers to compounds that are not toxic to cells. Compounds are biocompatible if their addition to cells in vitro results in less than or equal to 20% cell death, and their administration in vivo does not induce inflammation or other such adverse effects.

The term “biodegradable,” as used herein, refers to compounds that, when introduced into cells, are broken down into components that the cells can either reuse or dispose of without significant toxic effect on the cells (i.e., fewer than about 20% of the cells are killed when the components are added to cells in vitro). The components do not induce inflammation or other adverse effects in vivo. The chemical reactions relied upon to break down the biodegradable compounds are typically uncatalyzed. The term “effective amount,” as used herein with respect to an active agent, refers to the amount necessary to elicit the desired biological response. The effective amount of an agent or device may vary depending on such factors as the desired biological endpoint, the agent to be delivered, the composition of the encapsulating matrix, the target tissue, etc. Delivery of an “effective amount of a molecule” is the delivery of the molecule into a cell in sufficient amounts so that the molecule elicits a biological response, for example, modulating the expression of one or more genes in the cell. In specific embodiments, an effective amount of a molecule is delivered to a cell such that an amelioration or improvement in a disease, condition, or disorder related to the cell can be obtained. Delivery of an “effective amount of siRNA” or an “effective amount or RNAi” is the delivery of siRNA or other RNAi into a cell in sufficient amounts to cause a reduction in expression of the target gene in the cell.

The terms “biologically active agent”, “bioactive agents” or the like, generally refers to a composition, complex, compound or molecule which has a biological effect or that modifies, causes, promotes, enhances, blocks or reduces a biological effect, or that enhances or limits the production or activity of, reacts with and/or binds to a second molecules which has a biological effect. The second molecule can, but need not be, an endogenous molecule (e.g., a molecule, such as a protein or nucleic acid, normally present in the target cell). A biological effect may be, but is not limited to, one that stimulates or causes an immunoreactive response; one that impacts a biological process in a cell, tissue or organism (e.g., in an animal); one that imparts a biological process in a pathogen or parasite; one that generated or causes to be generated a detectable signal; one that regulates the expression of a protein or polypeptide; one that stops or inhibits the expression of a protein or polypeptide; or one that causes or enhances the expression of a protein or polypeptide. Biologically active compositions, complexes, compounds or molecules may be used in investigative, therapeutic, prophylactic and diagnostic methods and compositions and generally act to cause.

The term “cationic lipid” refers to any cationic lipids which may be used for transfection and which under physiological conditions possess at least one positive charge. While it is to be understood that certain of the cell surface ligands that form the basis of the present disclosure can be formulated with cationic lipids the cationic lipids can be considered helper lipids.

The term “lysosomotropic agent” is any compound or molecule which inhibit lysosomal function that prevents or slows the acidification of the lysosomal compartment.

The term “nucleic acid binding moiety” as used herein refers to a compound or molecule capable binding to nucleic acid. The binding molecule is capable of noncovalently binding to nucleic acid. The binding molecule is also capable of covalently linking to a cell binding adhesion sequence, a nuclear localization sequence and/or a fusion agent. The binding molecule can include but is not limited to spermine, spermine derivative, spermidine, histones or fragments thereof, protamines or fr fragments thereof, HMG proteins or fragments thereof, poly-lysine, poly-arginine, poly-histidine, polyamines and cationic peptides, nucleic acid intercalaters, protein nucleic acid sequences or aptamers. In addition, this includes but is not limited to analogs or derivatives of the above compounds. Non limiting examples are the cationic peptides that are repeats of lysine or arginine, for example a sequence having between 6-20 lysine residues (K6-K20) or between 6-20 arginine residues (R6-R20).

“Target cell” or “target tissue” refers to any cell or tissue to which a desired compound is delivered, using a lipid aggregate or transfection complex as carrier for the desired compound.

Transfection is used herein to mean the delivery of any nucleic acid, protein, peptide, cell nutrient, molecule or other macromolecule to a target cell or tissue in vitro or in vivo (i.e., in an animal, a plant or a human), such that the nucleic acid, protein, or macromolecule is expressed in, confers a phenotype to, causes enhanced growth or has a biological function in the cell. Delivery of exosomal material or nutrients is considered transfection.

The term “expressible nucleic acid” includes both DNA and RNA without regard to molecular weight, and the term “expression” means any manifestation of the functional presence of the nucleic acid within the cell including, without limitation, both transient expression and stable expression.

The term “fusion agent” as used herein refers to any chemical or molecules capable breaking down an endosomal membrane and freeing the transfection agent into the cytoplasm of the cell. This term includes but is not limited to viruses, synthetic compounds, proteins, fusion peptides, or derivatives thereof. As a result of the presence of the fusion agent the membrane can undergo lysis, fusion, or rearrangement or all three. Fusion agents can also cause direct fusion with the cell membrane.

The term “fusion peptide” refers to any peptide grouping which penetrates a membrane such that the structural organization and integrity of the membrane is lost. Fusion peptides are fusion agents.

The term “transfection agent” as used herein generally refers to composition capable of delivering molecules to cells. Transfection agents can be organic such as lipid, carbohydrate, cationic polymers, dendrimers, peptide or protein based or combination of those depending cell type or tissue that one targets. Transfection agents can also be in-organic such as calcium salts. They including cationic lipids, anionic lipids, cationic peptides, and cationic polymers. Transfection agent as used herein may optionally include at least one or more of the transfection compounds optionally in combination with one or more helper lipids, one or more pegylated lipids, optionally one or more targeting moieties, optionally one or more nuclear localization sequences, optionally one or more fusion agents, optionally one or more condensing agents, optionally one or more cell penetration agents and optionally one or more lysosomotropic agents.

The term “transfection enhancer” as used herein refers to a compound when added to a transfection agent increases the efficiency of transfection (i.e., increases the percent of cells transfected), increases the level of expression of a transfection agent, or reduces the requirement for the amount of nucleic acid or protein required to give a biological response, or any combination of the enhancements above.

The term “surface ligand” or “cell surface ligand” refers to a chemical or structure which will bind to a surface receptor of a cell. The term “cell surface receptor” as used herein refers to a specific chemical grouping on the surface of a cell to which the surface ligand can attach, contact or associate with. A surface ligand is a targeting moiety. Furthermore, surface ligands include anything which is capable of entering the cell through cytosis (e.g., endocytosis, potocytosis, and pinocytosis).

The term “transfection complex”, as used herein generally refers to a composition formulated for the delivery of a biologically active agent, such as a nucleic acid, a protein, a macromolecule, nutrient, or the like, to a cell or to a tissue in vivo or in vitro. Transfection complexes as used herein may include at least one or more of the transfection compounds or agents in combination with the biologically active compound to be delivered, optionally in combination with; one or more helper lipids, one or more pegylated lipids, one or more targeting moieties, one or more nuclear localization sequences, one or more fusion agents, one or more condensing agents, one or more cell penetration agents, and one or more lysosomotropic agents in addition to the bioactive agent that is to be delivered. For the purposes described herein, the term “transfection complex” may be thought of as a lipoplex or a lipid aggregate contacted with a bioactive agent. Thus, in some instances in the following disclosure, terms such as lipoplex, lipid aggregate and the like may be used to make reference a transfection complex that lacks the one or more bioactive agents or “payloads”.

The term “helper lipid”, as used herein, generally refers to a lipid that is suitable for use in the preparation and formation of transfection complexes disclosed herein. Suitable helper lipids may include, though are not limited to DOPE, DPhPE, saturated and unsaturated DPPE, saturated and unsaturated DMPE, DOPC, Lyso-PE (1-acyl-2-hydroxy-sn-gly cero-3-phospho ethanol amine), Lyso-PC (1-acyl-3-hydroxy-sn-gly cero-3-phosphocholine), 3-alkyloxy-2-hydroxy-1-acetamidopropane, 4-alkyloxy-3-hydroxy-1-acetamidopropane, 5-alkyloxy-4-hydroxy-1-acetamidopropane, cholesterols, cholesterol derivatives, sterols, including phytosterols, zoosterols and hopanoids, or any of the neutral or cationic lipids that are known to allow or to facilitate the introduction of exogenous bioactive molecules to the interior of a cell or of a tissue. In some embodiments, more than one helper lipid may be used in the formulation of the transfection complxes described herein. Exemplary though non-limiting neutral or cationic lipids contemplated for use in the preparation of the presently disclosed transfection complexes may include one or more lipids selected from the following: N-(2-bromoethyl)-N,N-dimethyl-2,3-bis(9-octadecenyloxy)-propanaminimun bromide (BMOP), dipalmitoylphosphatidylethanolamine 5-carboxyspermylamide (DDPES), DSPC, dioleoylphosphatidylethanolamine (DOPE), formulation of cetyltrimethylammonium bromide (CATB) and DOPE (CTAB:DOPE), 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), DMG, 1,2-dimyristloxyaminopropane (DMAP), dimyristoylphospatidylethanolamine (DMPE), DOMG, DMA, Dioleoylphosphatidylcholine (DOPC), dimyristoylphosphatidylcholine (DMPC), Dipalmitoylethylphosphatidylcholine (DPEPC), dioleoydimethylammonium chloride (DODAC), 1,3-di-oleoyloxy-2-(6-carboxyspermyl)-propylamid (DOSPER), N-[1-(2,3-dioleyloxy)propyl]-N,N,N-trimethylammoniumchloride (DOTMA), N-[1-(2,3-dipalmitoleoyloxy)propyl]-N,N,N-trimethylammoniumchloride (DPTMA), didoceyl methylammonium bromide (DDAB), N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethyl-ammonium methylsulfate (DOTAP), DOTAP.Cl, 3,β-N,(N,N′-dimethylaminoethane)-carbamoyl]cholesterol (DC-chol), 2-(sperminecarboxami do)ethyl)-N,N-dimethyl-lammonium trifluoroacetate (DO SPA), O,O′-ditetradecanoyl-N-(alphatrimethylammonioacetyl) diethanolamine chloride (DC-6-14), dicaproylphosphtidylethanolamine (DCPE), dilauryl oxypropyl-3-dimethylhydroxy ethylammonium bromide (DLRIE), 1,2-dioleoyl-3-dimethylammonium-propane (DODAP), Ethyl-PC, 2,3-dioleoyloxy-N-[2-(sperminecarboxamidoethyl]-N,N-di-met-hyl-1-propanaminium trifluoroacetate (DOSPA), dioctadecylamidoglycyl carboxyspermine (DOGS), N-[1-(2,3 dimyristyloxy)propyl]-N,N-dimethyl-N-(2-hydroxyethyl) ammonium bromide (DMRIE), Dioleoylethyl-phosphocholine (DOEPC), N-[1-(2,3-dioleoyloxy)propyl]-N-[1-(2-hydroxyethyl)]-N,N-dimethylammonium iodide (DOHME), N-(3-aminopropyl)-N,N-dimethyl-2,3-bi s (dodecyloxy)-1-prop animinium bromide/dioleylphosphatidylethanolamine (GAP-DLRIE:DOPE), dipalmitoylphosphatidylcholine (DPPC), 1,2-dioleoyl-sn-glycero-3-[phospho-rac-(3-lysyl(1-glycerol)).Cl (DOPG), N-lauroylsarcosine, (R)-(+)-limonene, lecithins (and derivatives thereof); phosphotidylethanolamine (and derivatives thereof); phosphatidylethanolamines, dioleoylphosphatidylethanolamine), diphytanoylphosphatidylethanolamine (DPhPE), dipalmitoylphosphatidylethanolamine (DPPE), dipalmiteoylphosphatidylethanolamine, 3β-[1-ornithinamidecarbamoyl]-cholesterol (O-Chol), palmitoyloleoylphosphatidylethanolamine (POPE); distearoylphosphatidylethanolamine; phosphotidylcholine; phosphatidylcholines, dipalmitoylphosphatidylcholine (DPPC) palmitoyloleoylphosphatidylcholine (POPC); distearoylphosphatidylcholine; phosphatidylglycerol; piperazine-based cationic lipids, a phosphatidylglycerol, dioleoylphosphatidylglycerol (DOPG), dipalmitoylphosphatidyl-glycerol (DPPG), distearoylphosphatidylglycerol; phosphatidylserine (and derivatives thereof); phosphatidylserines, dioleoyl- or dipalmitoylphosphatidylserine; a diquatemary ammonium salt; N,N′-dioleyl-N,N,N′,N′-tetramethyl-1,2-ethanediamine (TmedEce), N,N′-dioleyl-N,N,N′,N′-tetramethyl-1,3-propanediamine (PropEce), N,N′-dioleyl-N,N,N′,N′-tetramethyl-1,6-hexanediamine (HexEce), and their corresponding N,N′-dicetyl saturated analogues (TmedEce, PropEce and HexEce), a diphosphatidylglycerol; a fatty acid ester; a monocationic transfection lipid; 1-deoxy-1-[dihexadecyl(methyl)ammonio]-D-xylitol; 1-deoxy-1-[methyl(ditetra-decyl)ammonio]-Darabinitol; 1-deoxy-1-[dihexadecyl(methyl)ammonio]-D-arabinitol; a 1-deoxy-1-[methyl(dioctadecyl)-ammonio]-darabinitol, glycerol ester; sphingolipids; cardolipin; a cerebroside; a ceramide; and combinations thereof.

Helper lipids also include the neutral lipids cholesterol and other 3βOH-sterols, as well as derivatives thereof, phosphatidyl choline, or commercially available cationic lipid mixtures such as, for example, LIPOFECTIN® CELLFECTIN® (1:1.5 (M/M) formulation of N,N,N′,N″,N′″-tetramethyl-N,N,N′,N″,N′″-tetrapalmitylspermine (TMTPS) and dioleoyl phosphatidylethanolamine (DOPE), LIPOFECTACE®, GS 2888 CYTOFECTIN®, FUGENE 6®, EFFECTENE®, and LIPOFECTAMINE®, LIPOFECTAMINE 2000®, LIPOFECTAMINE PLUS®, LIPOTAXI®, POLYECT®, SUPERFECT®, TFXNT™, TRANSFAST™, TRANSFECTAM®, TRANSMESSENGER®, vectamidine (3-tetradecylamino-N-tert-butyl-N′-tetradecylpropionamidine (a.k.a. diC14-amidine), OLIGOFECTAMINE MessengerMAX, GeneIn™, TransfeX™, LipofectAmine 3000, Lipofectin®, DMRIE-C, CellFectin®, LipofectAce®, Fugene®, Fugene® HD, Tfx-10®, Tfx-20®, Tfx-50®, DNA-In, Transfectin™, SilentFect™, Effectene®, ViaFect™, DC-chol, GenePorter®, DharmaFect 1®, DharmaFect 2®, DharmaFect 3®, DharmaFect 4®, Escort™ III, Escort™ IV, DOGS among others. Also contemplated are any mixtures of combination of the above listed helper lipids.

The following patent documents, patent applications, or references are incorporated by reference herein in their entirety and in particular for their disclosure of transfection agents containing cationic and neutral helper lipids, which may be used in the transfection complexes disclosed herein: U.S. Pat. Nos. 6,075,012; 6,020,202; 5,578,475; 5,736,392; 6,051,429; 6,376,248; 5,334,761; 5,316,948; 5,674,908; 5,834,439; 6,110,916; 6,399,663; 6,716,882; 5,627,159; 7,915,230; 7,531,693; 8,034,977; 7,166,745; 5,994,109; 6,033,884; 6,150,168; 6,177,554; 6,083,741 6,458,026; 7,598,421; 7,820,624; 7,256,043; 7,704,969; 8,026,341; 7,145,039; 7,531,693; and 8,785,200; and International Publications WO 2004/063342, WO 0027795, WO 2004/105697, WO 2007/130073, WO 2012/142622, and WO 2013/158127,

The term “pegylated lipid” as used herein generally refers to a lipid that is covalently conjugated to one or more polyethylene glycol moieties. Pegylated lipids for lipoplex embodiments herein include phosphatidylethanolamine (PE) based pegylated lipids such as, for example, 1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-MW] where MW refers to average MW of the polyethylene glycol moiety. Such dimyristoyl-PEG-PE lipids are commonly designated 14:0 PEG (MW) PE. The average MW of the polyethylene glycol moiety can be 25, 350, 550, 750, 1000, 2000, 3000, 5000, 6000, 8000 or 12000, for example. The fatty acid chains of the phosphatidylethanolamine based pegylated lipids may include, for example, a 1,2-dioleoyl group such as for 18:1 PEG (MW) PE, a 1,2-dipalmitoyl group such as for 16:0 PEG (MW) PE, or a 1,2-distearoyl-group such as for 18:0 PEG (MW) PE. Further phosphatidylethanolamine (PE) based pegylated lipids include, for example, 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[MOD(polyethylene glycol)-MW], also referred to as DSPE-MOD PEG(MW) wherein MOD refers to a functional moiety such as an amine, biotin, carboxylic acid, folate, maleimide, PDP, or carboxyfluorescein moiety. The MW may be 2000 or 5000, for example. Pegylated lipids for the embodiments described herein also include ceramide based pegylated lipids such as, for example, N-octanoyl-sphingosine-1-{succinyl[methoxy(polyethylene glycol)MW]}, designated C8 PEG (MW) ceramide, where MW is 750, 2000, or 5000, for example. Alternatively, the fatty acid moiety may have an N-palmitoyl (C16) group such as for C16 PEG (MW) ceramide.

A “liposomal composition” generally is a formulation that includes one or more liposomes. In some instances, the term “liposomal composition” may be used interchangeably with the term “transfection complex”. These formulations are typically colloids, but can be dried formulations as well. A liposome is a vesicular colloidal particle composed of self-assembled amphiphilic molecules. Surface ligands disclosed herein can be incorporated into liposomal compositions of one or more cationic lipids, or one or more anionic lipids either or one or more pH sensitive lipids alone or optionally in combination with one or more helper lipids (i.e., a neutral lipid, a cholesterol or cholesterol derivative, lysolipid. or cationic lipids) that are processed using standard methods to form a liposome-containing colloid suspension. Liposomal compositions disclosed herein are those containing one or more cationic lipids, one or more helper lipids, optionally, in combination with one or more neutral and/or helper lipids, targeting moieties, fusion agents, lysomotropic agents which are treated by any of the standard methods known in the art without limitation to form liposomes. The liposomal compositions may optionally contain one or more fusion agents. The liposomal compositions may optionally contain one or more liposomal compositions can be distinguished one from another by particle size measurements. Different compositions will exhibit differences in particle size and uniformity of particle size, e.g., average particle size, and polydispersity. Different compositions will exhibit differences in the extent of the composition that is in the form of liposomes. In some non-limiting embodiments, liposomal compositions will exhibit particle size in the range 120 nm and 800 nm and will exhibit generally lower polydispersity. Lipoplex particle size (with siRNA or other cargo) may range from about 40 nm to 135 nm. In some embodiments, lipoplex particle size is 50 nm to 120 nm, 50 nm to 100 nm, 60 nm to 90 nm, 70 nm to 90 nm, or about 85 nm.

The term “Lipid aggregate” or “lipoplex” is a generic term that includes liposomes of all types, both unilamellar and multilamellar, as well as vesicles, micelles and more amorphous aggregates. A cationic lipid aggregate is a lipid aggregate comprising a combination of one or more cationic compounds, optionally in combination with non-cationic lipids (including neutral lipids), such that the lipid aggregate has a net positive charge. Surface ligands of the present invention can be incorporated into lipid aggregate, optionally with a helper lipid and further optionally with one or more pegylated lipids and/or one or more targeting moieties, one or more fusion agents, and one or more lysosomotropic agents which can then form a lipid-bioactive agent complex when contacted with a suitable bioactive agent. The terms “lipid aggregate” or “lipoplex” are generally used herein to refer to a “naked” transfection complex, i.e., a transfection complex that generally lacks a payload of bioactive agent to be delivered to a cell or to a tissue in vitro or in vivo.

The term “exosome” refers to the small membrane vesicles secreted by most cells that contain cell specific payloads of proteins, lipids and, genetic material and other biomolecules that are transported to other cells in different location of the tissue.

The term “lipid-bioactive agent” generally refers to the noncovalent association between a lipid or lipid aggregate and a bioactive agent, such as a nucleic acid, a polypeptide, and the like.

As used herein “nucleic acid” and its grammatical equivalents will include the full range of polymers of single or double stranded nucleotides and includes nucleic acids (including DNA, RNA, and DNA-RNA hybrid molecules, locked nucleic acids (LNA), Bridged Nucleic acid (BNA)); nucleic acids that are prepared in vitro, using techniques such as PCR amplification or chemical synthesis; that are prepared in vivo, e.g., via recombinant DNA technology; or that are prepared or obtained by any known method. A nucleic acid typically refers to a polynucleotide molecule comprised of a linear strand of two or more nucleotides (deoxyribonucleotides and/or ribonucleotides) or variants, derivatives and/or analogs thereof. The exact size will depend on many factors, which in turn depends on the ultimate conditions of use, as is well known in the art. The nucleic acids of the present invention include without limitation primers, probes, oligonucleotides, vectors, constructs, plasmids, genes, transgenes, genomic DNA, cDNA, LNA, BNA, RNA, mRNA, tRNA, miRNA, RNAi, siRNA, shRNA, stRNA, guide-RNA, PCR products, gBlock oligos, restriction fragments, oligonucleotides and the like.

As used herein, the term “nucleotide” includes any monomeric unit of DNA or RNA containing a sugar moiety (pentose), a phosphate, and a nitrogenous heterocyclic base and may also include mono-, di- and triphosphate forms of such nucleotides. The base is usually linked to the sugar moiety via the glycosidic carbon (at the 1′ carbon of pentose) and that combination of base and sugar is called a “nucleoside.” The base characterizes the nucleotide with the four customary bases of DNA being adenine (A), guanine (G), cytosine (C) and thymine (T). Inosine (I) is an example of a synthetic base that can be used to substitute for any of the four, naturally occurring bases (A, C, G, or T). The four RNA bases are A, G, C, and uracil (U). Accordingly, a nucleic acid may be a nucleotide sequence comprising a linear array of nucleotides connected by phosphodiester bonds between the 3′ and 5′ carbons of adjacent pentoses. Other modified nucleotides are known and may be sued in the practice of the invention. The term nucleotide includes ribonucleoside triphosphates ATP, UTP, ITP, CTG, GTP or derivatives such as but not limited to [αS] ATP, 7-deaza-GTP and 7-deaza-ATP, 5-methyCTP, pseudoUTP, 4-thioUTP and deoxyribonucleoside triphosphates such as dATP, dCTP, dITP, dUTP, dGTP, dTTP, or derivatives thereof. Such derivatives include, for example, [αS]dATP, 7-deaza-dGTP and 7-deaza-dATP, 5-methydCTP, pseudodUTP, 4-thiodUTP, LNA-Nucleosidetriphosphates and nucleotide derivatives that confer nuclease resistance on the nucleic acid molecule containing them. The term nucleotide as used herein also refers to dideoxyribonucleoside triphosphates (ddNTPs) and their derivatives. Illustrated examples of dideoxyribonucleoside triphosphates include, but are not limited to, ddATP, ddCTP, ddGTP, ddITP, and ddTTP. The term nucleotides as used here also refer to nucleotides that contain modifiable groups. Illustrated examples of nucleotides with modifiable group include, but are not limited to, allyamine-CTP, allyamine dCTP, allyamine UTP, allyamine dUTP. According to the present invention, a “nucleotide” may be unlabeled or detectably labeled by well-known techniques. Detectable labels include, for example, biotin, radioactive isotopes, fluorescent labels, chemiluminescent labels, bioluminescent labels and enzyme labels. Various labeling methods known in the art can be employed in the practice of this invention. Transfection complexes of this invention can be used to deliver nucleotides to living cells to allow incorporation of modified nucleotides in nucleic acids.

“RNA” or “RNA molecule” refers to any RNA molecule or functional portion thereof, of any size and having any sequence, from any source, including RNA from viral, prokaryotic, and eukaryotic organisms. The RNA molecule may be chemically modified and in any form, including, but not limited to, linear or circular, and single or double stranded. Non-limiting examples of RNA molecules include mRNA, rRNA, tRNA, miRNA, mtRNA, tmRNA, RNAi, siRNA, shRNA, guideRNA, and stRNA. In some embodiments, siRNA molecules useful in the practice of the invention include, for example, those described in U.S. Patent Publication Nos. 2004/0014956, 2004/0054155, 2006/0009409, 2009/0023216, and 2010/0136695; and as described in International Publications WO 2003/064626, and WO 03/064625, all of which are incorporated by reference herein. Further siRNA molecules useful in the practice of the invention include, for example, those described in International Publication WO 2009/039173, which application is incorporated by reference herein.

The terms “peptide”, “polypeptide”, or “protein,” as used herein refer to a string of at least three amino acids linked together by peptide bonds. The terms “protein” and “peptide” may be used interchangeably, though it is generally understood that a “polypeptide” or “protein” is larger than a peptide. “Peptide” may refer to an individual peptide or a collection of peptides.

The terms “polynucleotide” or “oligonucleotide,” as used herein, refer to a polymer of nucleotides. Typically, a polynucleotide comprises at least three nucleotides. The polymer may include natural nucleosides (i.e., adenosine, thymidine, guanosine, cytidine, uridine, deoxyadenosine, deoxythymidine, deoxyguanosine, and deoxycytidine), nucleoside analogs (e.g., 2-aminoadenosine, 2-thiothymidine, inosine, pyrrolo-pyrimidine, 3-methyl adenosine, C5-propynylcytidine, C5-propynyluridine, C5-bromouridine, C5-fluorouridine, C5-iodouridine, C5-methylcytidine, 7-deazaadenosine, 7-deazaguanosine, 8-oxoadenosine, 8-oxoguanosine, O(6)-methylguanine, and 2-thiocytidine), chemically modified bases, biologically modified bases (e.g., methylated bases), intercalated bases, modified sugars (e.g., 2′-fluororibose, ribose, 2′-deoxyribose, arabinose, and hexose), or modified phosphate groups (e.g., phosphorothioates and 5′-N-phosphoramidite linkages). The term “lipid” refers to hydrophobic or amphiphilic organic compounds inclusive of fats, oils and triglyderides.

Disclosed Aspects and Embodiments

Transfection complexes suitable for the delivery of one or more biologically active agents to a cell or a tissue in vitro or in vivo are provided for herein. The transfection complexes described herein include one or more cell surface ligands that enhance transfection in combination with a transfection agent as part of a transfection complex. In some embodiments, the transfection complexes disclosed herein optionally further comprise one or more components selected from the group consisting of one or more helper lipids, one or more pegylated lipids, one or more cationic lipids, one or more cationic polymers one or more targeting moieties, and a combination thereof. In some embodiments, transfection complexes disclosed herein further comprise one or more components selected from the group consisting of peptide or non-peptide transfection enhancers, fusogenic peptide or non-peptide fusion agents, peptide or non-peptide endosomal release agents, cell penetration agent, lysomolotropic agents, nuclear targeting agents (such as, e.g., a peptide containing one or more nuclear localization sequences), and a combination thereof.

In some embodiments, helper lipids suitable for use in the preparation and formation of transfection complexes disclosed herein include, though are not limited to a cholesterol, a cholesterol derivative, one or more sterols, including phytosterols, zoosterols and hopanoids, or any of the neutral or cationic lipids that are known to allow or to facilitate the introduction of exogenous bioactive molecules to the interior of a cell or of a tissue. In some embodiments, more than one helper lipid is used in the formulation of the transfection complexes described herein. In some embodiments, the transfection complexes disclosed herein comprise no helper lipid.

Illustrative though non-limiting neutral or cationic lipids suitable for use as helper lipids in accordance with some of the embodiments set forth herein include saturated and unsaturated alkyl and alicyclic ethers and esters of amines, amides or derivatives thereof. In some embodiments, straight-chain or branched alkyl and alkene groups of cationic lipids contain from 1 to about 25 carbon atoms. In certain embodiments, straight-chain or branched alkyl or alkene groups have six or more carbon atoms. In some embodiments, straight-chain or branched alkyl or alkene groups have eight to about twenty carbon atoms. In other embodiments, alicyclic groups contain from about 6 to 30 carbon atoms, or, alternatively, eight to twenty carbon atoms. In some embodiments, the alicyclic groups include cholesterol and other steroid groups. In certain embodiments, cationic lipids are prepared with a variety of counter ions (anions) including among others: a halide (i.e., Cl⁻, Br⁻, I⁻, F⁻), acetate, trifluoroacetate, sulfate, nitrite, triflate, and nitrate

Embodiments of pegylated lipids suitable for use in the preparation and formation of the transfection complexes disclosed herein are any lipid or mixture of lipids that are compatible with the formation of transfection complexes described herein, and with the administration thereof to an animal or to a human in vivo, or to tissues or cells in vitro. The pegylated lipids used with the presently described transfection complexes include, but are not limited to, a PEG polymer having a molecular weight between about 250 daltons and about 12,000, or in some embodiments, about 350 daltons and about 6,000 daltons, or, in some embodiments, between about 500 daltons and about 1,000 daltons, or, in some embodiments, between about 1,000 daltons and about 2,000 daltons, or, in some embodiments, between about 2,000 daltons and 5,000 daltons.

In some embodiments, the presently disclosed transfection complexes include one or more biologically active agents to be delivered to a cell or to a target tissue in vitro or in vivo. Suitable biologically active agents include, but are not limited to, any molecule that is capable of forming a transfection complex with the presently described transfection reagents and that elicits a biological response when delivered to the interior of a cell or cells or to a tissue in vivo or in vitro. In some embodiments, biologically active agents contemplated for use in the presently described embodiments are cationic, neutral or anionic agents. In some embodiments, the biologically active agents suitable for formulation in the presently disclosed transfection complexes include a DNA or RNA molecule, either alone or in combination with other DNA or RNA molecules in various combinations, though are not limited to; nucleic acids (including but not limited to single or double stranded linear or circular DNA molecules including cDNA molecules, single or double stranded RNA molecules, mRNA, modified mRNA that has increase stability, small interfereing RNA (siRNA) molecules, small hairpin RNA (shRNA) molecules, guideRNA (gRNA), CRISPR-Cas9/guideRNA, microRNA (miRNA) molecules, oligonucleotides, anti-sense oligonucleotides, sense oligonucleotides), polypeptides, antibodies, oligopeptides, therapeutic peptides or protein molecules, peptide nucleic acids (PNAs), cationic, anionic or neutral organic molecules or drugs, in addition to pharmaceutically acceptable salts thereof. In another embodiment nutrients required for cell growth or than can be used to enhance protein expression can be delivered into cells.

In certain non-limiting illustrative embodiments, the transfection complexes disclosed herein deliver nucleic acid molecules into cells or tissues in vitro or in vivo, including the delivery of RNA interference molecules (RNAi) or small interfering RNA molecules (siRNA, shRNA or miRNA) into cells for inhibition of gene expression.

In some embodiments, the cell surface ligands of the presently disclosed transfection complexes are used to deliver mRNA molecules or mixtures of mRNA and DNA molecules into a cell or a tissue in vivo or in vitro to promote the expression of a specific protein or proteins. mRNA reprograming molecules or telomerase are non-limiting examples of mRNA molecules. Cas9 mRNA and DNA molecules that code for gRNA, CRE mRNA and LoxP containing DNA molecules, SV40T antigen mRNA and DNA molecules with the SV40 origin of replication are non-limiting examples of mRNA and DNA pairs that have utility. Preformed transfection complexes that contain mRNA are non-limiting illustrative embodiments of transfection complexes disclose herein. Telomerase mRNA transfection complexes as a media supplement are disclosed herein. In some embodiments, preformed transfection complexes containing mRNA are made and the DNA molecule is added to the complex at a later time.

In some embodiments, the cell surface ligands of the presently disclosed transfection complexes are used to deliver DNA molecules (including cDNA molecules) into a cell or a tissue in vivo or in vitro to promote the expression of a specific protein or proteins or to synthesize specific RNA molecules, including but not limited to mRNA molecules or RNAi or miRNA or shRNA molecules are also provided.

In some embodiments, the cell surface ligands of the presently disclosed transfection complexes are used to deliver proteins or protein nucleic acid complexes into a cell or a tissue in vivo or in vitro to effect the function of the protein, as for example in gene editing. In some embodiments, the transfection complexes described herein contain one or more fusogenic peptides, one or more nuclear targeting peptide, one or more cationic lipid, or one or more neutral lipid. Non-limiting examples of proteins and protein nucleic acid complexes include Cre recombinase and Cre fusion proteins, transcription activator like effector nucleases (TALEN), and CRISPR-Cas9 nuclease/guide RNA complex.

In some embodiments various DNA, RNA and/or proteins are delivered together, such as Cas9 protein, with gRNA, sgRNA, gBlock oligos, and or ssDNA.

In some embodiments, proteins such as RNA polymerase, RNA binding proteins or peptides, and transcription factors are bound to nucleic acids and are delivered to cells with the transfection reagents disclosed herein. In certain embodiments, proteins are made anionic by the addition anionic peptides or anionic polymers designed to attach to the protein or an anionic amino acid is added to the C-terminus or N-terminus of the protein.

In some embodiments, the transfection complexes described herein may optionally include one or more fusogenic or cell-penetrating peptides. A fusogenic or cell-penetrating peptide is any peptide molecule that is capable of promoting the fusion of a lipid-containing complex to a cell membrane (either a plasma membrane or an endosomal membrane). A variety of fusogenic or cell-penetrating peptides are known in the art and it is well within the skill level of a practitioner to identify suitable fusogenic or cell-penetrating peptides and condition for the use thereof in the present invention without undue experimentation.

In some embodiments, the transfection complexes described herein optionally include one or more transfection helpers or targeting moieties in combination with the cell surface ligands described herein. In some embodiments, the targeting moiety is a peptide, a modified peptide, an antibody, a modified antibody, a receptor molecule, a modified receptor molecule, a single or a double stranded nucleic acid molecule, a modified single or double stranded nucleic acid molecule, a peptide or nucleic acid aptamer, a modified peptide or nucleic acid aptamer, an organic molecule, a polysaccharide, or any other molecule that is capable of targeting a transfection complex to specific tissue or cell type for targeted delivery of a biologically agent thereto, such as will be readily apparent to those having ordinary skill level in the art. In some embodiments, modification of a peptide, an antibody, a nucleic acid, an aptamer, and the like includes conjugating the peptide, antibody, nucleic acid, aptamer, and the like to a PEG moiety. Alternatively, said modification includes conjugating the peptide, antibody, nucleic acid, aptamer, and the like to a PEG-lipid moiety. A variety of targeting moieties are widely known to those skilled in the art, and all are contemplated for use with the presently described embodiments, without limitation.

In some embodiments, the transfection complexes disclosed herein are stable for up to one year and are either contacted with the cells or tissues to be transfected, or are administered to a subject immediately or shortly after being formed. In some embodiments, the transfection complexes disclosed herein are optionally stored for a period of time prior to being contacted with the cells or tissues, or being administered to a subject. The transfection complexes are stable and may be stored for a time period of at least 30 minutes, at least 45 minutes, at least 1 hour, at least 2 hours, at least 3 hours, at least 4 hours, at least 5 hours, at least 10 hours, at least 15 hours, at least 20 hours, at least 24 hours, at least 48 hours, at least 72 hours, at least 5 days, at least 7 days, at least 14 days, at least 28 days, at least 1 month, at least 2 months, at least 3 months, at least 4 months, at least 5 months, at least 6 months or at least 1 year at room temperature, or at a temperature greater than freezing, up to about room temperature. In some embodiments, the formulations described herein include one or more stabilizing agents, preservatives, buffers, and the like, that aid in the long-term stabilization and storage of bioactive formulation, such as will be readily understood by the skilled practitioner of the biological and pharmaceutical arts, and without requiring undue experimentation to achieve. It is also understood, that the storage period can be between any of the aforesaid time periods, for example between 31 minutes and 1 hour or between 1 hour and 24 hours.

In another aspect, disclosed herein are methods for the preparation of functional transfection complexes containing cell surface ligands, the complexes being as described herein. In some embodiment the functional transfection complex may be used for the preparation of synthetic exosomes that contain biologically active macromolecules. In some embodiments, the methods include the step of forming a lipid-aggregate by encapsulating a biologically active agent in a composition containing one or more surface ligands described herein, optionally in combination with one or more helper lipids, stabilizing lipids, transfection helpers, pegylated lipids, targeting moieties, fusion agents, lysosomotropic agent. In some embodiments, the methods alternatively include: 1) mixing one or more surface ligands, with one or more transfection compounds, which optionally include one or more helper lipids, stabilizing lipids, transfection helpers, targeting moieties, fusion agents, lysosomotropic agent, optionally with one or more pegylated lipids, or a salt thereof, in an alcohol/aqueous solution wherein the alcohol concentration is <50%; 2) mixing one or more surface ligands, with one or more transfection compounds, which optionally include one or more helper lipids, stabilizing lipids, transfection helpers, targeting moieties, fusion agents, lysosomotropic agent, and one or more pegylated lipids, or a salt thereof, in a molar percentage such that the one or more transfection compounds are present at 1%-50%; 3) mixing one or more surface ligands, with one or more transfection compounds, which optionally include one or more helper lipid, stabilizing lipids, transfection helpers, targeting moieties, fusion agents, lysosomotropic agent, one or more pegylated lipids, or a salt thereof, in a molar percentage such that the Pegylated lipids are present at <50%; and 4) mixing one or more surface ligands, with one or more transfection compounds, which optionally include one or more helper lipid, stabilizing lipids, transfection helpers, targeting moieties, fusion agents, lysosomotropic agent, one or more pegylated lipids, or a salt thereof, wherein the pegylated lipid has a polyethylene glycol molecular weight of about 2000-12000 and a fatty acid chain length of C6-C20 alkyl, or C10-C20 alkenyl; and complexing the lipid aggregate in an alcohol/aqueous solution with the bioactive agent to form a transfection complex, wherein the alcohol concentration is <50%, preferably less than 40%. In some embodiments, the alcohol is ethanol. In some embodiments, the alcohol is a pharmaceutically acceptable alcohol such as an alcohol that is liquid at about room temperature, for example, ethanol, propylene glycol, 2-(2-ethoxyethoxy)ethanol (Transcutol™), benzyl alcohol, glycerol, polyethylene glycol 200, polyethylene glycol 300, polyethylene glycol 400 or a mixture thereof. In some embodiments, the alcohol for mixing is different than the alcohol for complexing. Formulations of lipid aggregates as provided above can be provided in 0% to 100% ethanol. In some embodiments, the helper lipid is a neutral lipid. The ratio of cationic to neutral lipid can vary from 100% to 1% cationic lipid.

In another embodiment preformed lipid aggregates or liposomes containing cationic, anionic, and or neutral lipids are mixed with cell surface ligands describe herein. In certain embodiments, the lipid aggregates or liposomes are optionally formulated with one or more transfection enhancers such as helper lipids, stabilizing lipids, transfection helpers, pegylated lipids, other targeting moieties, fusion agents, and or lysosomotropic agents. In some embodiments, the cell surface ligands described herein are added to these formulations at any point prior to or after the bioactive agent is loaded into the transfection complex.

In another embodiment a mixture of cationic lipid and neutral lipids are dissolved in organic solvent such as chloroform and mixed with aqueous solutions optionally containing buffers and one or more cell surface ligands, and optionally one or more transfection enhancers, one or more fusion agents, one or more nuclear localization agents and subjected to reveres evaporation to remove the organic solvent leaving behind a lipid aggregate or liposome in solution.

In another embodiment, a mixture of cationic lipids and neutral lipid is added to an aqueous solution containing buffers and one or more cell surface ligands, and optionally one or more transfection enhancers, one or more fusion agents, one or more nuclear localization agents and this solution is micro fluidization or sonicated to form lipid aggregates or liposomes.

In another aspect, disclosed herein are methods for screening for a tissue-based delivery of a transfection complex or cell type. In some embodiments, the method comprises the step of preparing a plurality of transfection complexes, each transfection complex having at least one test cell surface ligand in combination with at least one nucleic acid that facilitates detection of delivery to a tissue or cell type. In some embodiments, the nucleic acid is an RNA molecule or a DNA molecule that encodes a protein that can be directly detected (such as, e.g., Green Fluorescent Protein (GFP), Red Fluorescent Protein, Luciferase, or the like), or encode a protein that effects expression of a protein that can be directly detected.

In an embodiment, a method for screening for a cell based or tissue-based delivery of at least one test cell surface ligand comprises the step of preparing a plurality of unique transfection complexes, each transfection complex having at least one test cell surface ligand in combination with an mRNA or a cDNA that encodes the detectable protein or a specific transcription factor. Each unique transfection complex is delivered either to cells in culture, intravenously, subcutaneously, or to a tissue to a subject. After a predetermined amount of time, cells in culture or tissues from the subject are harvested and the expression of the detectable protein in various tissues is detected by gross examination, histological examination or by molecular detection (PCR, Western blotting, or the like), or imaged in vivo using the IVIS® Imaging System (Caliper), to determine to which tissue or tissues the transfection complexes containing specific transfection compounds are delivered.

In an embodiment, a method for screening cells in culture or tissue-based delivery of a transfection complex comprises the step of preparing a plurality of unique transfection complexes, each transfection complex having at least one test least one test cell surface ligand in combination with an mRNA or a cDNA that encodes a specific transcription factor. Each unique transfection complex may be delivered to cells in culture, intravenously, subcutaneously, or to a tissue to a transgenic animal that expresses a reporter gene (such as, e.g., luciferase) under the control of the specific transcription factor. After a predetermined amount of time, tissues from the transgenic animal may be harvested and the expression of reporter gene in various tissues may be detected by gross examination, histological examination or by molecular detection (PCR, Western blotting, or the like). If the reporter gene is luciferase, detection may be accomplished in-vivo using the IVIS® Imaging System (Caliper).

In some embodiments, the cell surface ligands of the presently disclosed transfection complexes are used to deliver exosomes into a cell or a tissue in vivo or in vitro to effect the function of the biological cargo in the exosomes. In some embodiments, the transfection complex described herein comprise one or more fusogenic peptides, one or more nuclear targeting peptide, one or more cationic lipid, or one or more neutral lipids. In certain embodiments, the transfection complexes described herein comprise one or more of the cationic lipids described in Formula I.

In another aspect, disclosed herein are compositions and methods that provide improved efficiency for introducing macromolecules, such as nucleic acids, proteins, peptides, and pharmaceuticals into cells. Accordingly, provided herein are transfection complexes comprising a nucleic acid molecule, a transfection agent and a transfection enhancer.

In some embodiments, the transfection enhancer is a surface ligand that comprises amino acid sequences derived from a cell binding adhesion proteins. Collagen, fibronectin, lamin, veronectin, cadherin, nidogen, fibrinogen, elastin, bone asialoprotein, osteopontin and tenascin-C are non-limiting examples of cell binding adhesion proteins. In some embodiments, the surface ligand is the above-listed full-length protein. In other embodiments, the surface ligand is a fragment of the above-listed protein having greater than 5 amino acids in length. In other embodiments, the length of the fragment of the above-listed protein is greater than 10 amino acids, greater than 15 amino acids, greater than 20 amino acids, greater than 25 amino acids, greater than 30 amino acids, greater than 35 amino acids, or greater than 40 amino acids.

In some embodiments, the cell surface ligands derived from cell adhesion proteins and describe herein comprise a nucleic acid binding moiety functionally linked to the amino acid sequence of the cell surface ligand peptide derived from adhesion proteins. Suitable nucleic acid binding moieties include, but are not limited to, a polycationic peptide sequence, a polyamine, a peptide nucleic acid, spermine, spermidine, carboxyspermidine, carboxy spermine, spermine and spermidine analogs, nucleic acid intercalaters, and the like. In certain embodiments, the nucleic acid binding moiety is covalently linked to the transfection promoting cell surface ligand comprising adhesion protein amino acid sequences. In further embodiments, the transfection agent is a cationic lipid, such as those described below, a polyamine, a polycationic peptide sequence, a cationic dendrimer, or the like. In some embodiments, the cell surface ligand adhesion sequence is a multimer of itself or other adhesion sequences. In certain embodiments, the cell binding adhesion amino sequence is cyclized. In other embodiments, the surface ligands also contain other peptide sequence that enhance transfection efficiency, such as linkers, spacers, or nuclear targeting sequences.

In some embodiments, the cell surface ligand peptide sequences described herein are attached directly to the binding molecule by covalent bonding, or are connected to the binding molecule via a spacer. The term “spacer,” or “linker,” which are used interchangeably herein, as used herein refers to a chemical structure that links two molecules to each other. In some embodiments, the spacer binds each molecule on a different part of the spacer molecule. In other embodiments, the spacer is a hydrophilic moiety and comprises about 6 to 30 carbon atoms. In other embodiments, the spacer comprises a polyether, for example —CH₂—O—(CH₂—CH₂—O—)_(i)CH₂—. In other embodiments, the spacer comprises a hydrophilic polymer, for example [(gly)_(i)(ser)_(j)]_(k). In these formulae i ranges from 1 to 6, j ranges from 1 to 6, and k ranges from 3 to 20. In some embodiments, the spacer is a peptide of sequence APYKAWK (SEQ ID NO:505). In other embodiments, the spacer is a sequence that is degraded in vivo by a peptidase.

In some embodiments, the cell surface ligand peptide sequences described herein are functionally linked to a lipid, such as a cationic or neutral lipid. In some of these embodiments, the linked moiety is used for delivery of macromolecules into cells. For example, a cell binding adhesion peptide sequences amino acid sequence is covalently linked to a lipid, such as a cationic lipid, using methods known in the art.

In certain embodiments, the cell surface ligand peptide sequences described herein also are functionally linked to an amino acid sequence that inserts itself into lipid membranes, such as membrane anchor peptides or proteins. In other embodiments, the cell surface ligand peptide sequences are linked to chemical compositions that associate with lipids.

In other embodiments, the transfection complexes or liposomal compositions with the cell surface ligand peptide sequences described herein also comprise other transfection enhancing agents, such as a nuclear localization protein or peptide, a fusogenic peptide or protein, a transport peptide or protein, a viral peptide or protein, a cell penetration protein, or a lysomoltropic agent. In certain embodiments, the viral peptide is derived from a virus, for example an influenza virus, a vesicular stomatitis virus, an adenovirus, an alphavirus, a Semliki Forest Virus, a hepatitis virus, a herpes virus, an HIV virus, or a simian virus. In some embodiments, the transfection enhancing agent is, for example, insulin, a transferrin, a epidermal growth factor, a fibroblast growth factor, a cell targeting antibody or fragment from an antibody, a lactoferrin, a fibronectin, an adenovirus penton base, Knob, a hexon protein, a vesicular stomatitis virus glycoprotein, a Semliki Forest Virus core protein, an influenza hemagglutinin, a hepatitis B core protein, an HIV Tat protein, a herpes simplex virus VP22 protein, a histone protein, an arginine rich cell permeability protein, a high mobility group protein, and invasin protein, an internalin protein, an endotoxin, a diptheria toxin, a shigella toxin, a melittin, a magainin, a gramicidin, a cecrophin, a defensin, a protegrin, a tachyplesin, a thionin, a indolicidin, a bactenecin, a drosomycin, an apidaecin, a cathelicidin, a bacteriacidal-permability-increasing protein, a nisin, a buforin, or fragments thereof. In other embodiments, the transfection enhancing agent is chloroquine, a lysosomotrophic compound or combinations thereof. In other embodiments, the transfection enhancer agent comprises multimers of the same or different peptides or proteins.

Suitable nuclear localization peptides or proteins included in transfection complexes or liposomal compositions include, but are not limited to, a sequence selected from the group consisting of SEQ ID NOs:1-41, as set forth in Table 1, below, or in the sequence listings.

Proteins such as histones, protamines, HMG proteins, and viral core proteins comprise nuclear localization proteins. In some embodiments, these proteins are used to enhance transfection. In some embodiments, the nuclear localization peptide is optionally linked to a nucleic acid binding moiety, for example via a covalent linkage. Spacer sequences are optionally used between the DNA binding sequence and the nuclear localization sequence. In some embodiments, the nuclear localization sequences are linked to helper lipids or other peptides proteins or compounds that associate with lipid bilayers.

In some embodiments, the compositions described herein also comprise a fusion agent or combinations of fusion agents, which in some embodiments also function as an amphipathic peptide. Suitable fusion peptides include, but are not limited to, a sequence selected from the group consisting of SEQ ID NOs:42-92, as set forth in Table 1, below, or in the sequence listings.

In some embodiments, the fusion agent is optionally linked to a nucleic acid binding moiety, for example via a covalent linkage. The peptides KK, KKK, KKKK (SEQ ID NO:97), RR, RRR, RRRR (SEQ ID NO:105) can be linked to fusion agents of SEQ ID NOs:42-92. In certain embodiments, fusion peptides are linked to helper lipids, cationic lipids, or other peptides or proteins that associate with lipid bilayers.

In certain embodiments, the compositions disclosed herein comprise a cell penetration agent or combinations of cell penetration agents. Suitable cell penetration agents include, but are not limited to, a sequence selected from the group consisting of SEQ ID NOs:93-96 as set forth in Table 1, below, or in the sequence listings.

In some embodiments, the cell penetration agents are optionally linked to a nucleic acid binding moiety, for example via a covalent linkage. In other embodiments, the cell penetration agents are linked to helper lipids or other peptides or proteins that associate with lipid bilayers.

In some embodiments, the nuclear localization sequences, the fusion agents, cell surface ligand or the cell penetration agents are linked to the GPI anchor peptides, the sequence FTLTGLLGTLVTMGLLT (SEQ ID NO:504) being a non-limiting example.

In some embodiments, the nucleic acid binding moieties that are linked to different transfection enhancer and are part of transfection complexes have different binding affinity for nucleic acids depending on the needed functionality for attachment, condensation of nucleic acid, and the rate of release of nucleic acid from the nucleic acid binding moiety. Suitable nucleic acid binding moieties include, but are not limited to a polycationic peptide sequence, a polyamine, a peptide nucleic acid, spermine, spermidine, carboxyspermidine, carboxy spermine, spermine and spermidine analogs, nucleic acid intercalaters, and the like.

In some embodiments, the compositions described herein comprise combinations of different transfection enhancers with different nucleic acid binding moieties. Suitable nucleic acid binding peptides include, but are not limited to a sequence of SEQ ID NOs:97-149, as set forth in Table 1, below, or in the sequence listings.

In some embodiments, the nucleic acid binding moieties also serve as transfection enhancers when bound to nucleic acids, or alternatively serve as condensing agents. Suitable nucleic acid condensing peptides include, but are not limited to, a sequence selected from the group consisting of the peptides of SEQ ID NOs:97-149 as set forth in Table 1, below, or in the sequence listings. In some embodiments, multimers of these peptides are also synthesized and used as condensing agents. In some embodiments, nuclear localization sequences are also used as condensing agents if they have enough cationic charge.

Suitable nucleic acid binding moieties include, but are not limited to a polycationic peptide sequence, a polyamine, a peptide nucleic acid, spermine, spermidine, carboxyspermidine, carboxy spermine, spermine and spermidine analogs, nucleic acid intercalaters, and the like

One skilled in the art will readily recognize that the surface ligand chosen depends on which receptor is being bound. Since different types of cells have different receptors, this provides a method of targeting nucleic acid, peptides, protein, and compounds to specific cell types, depending on which cell surface ligand is used. Thus, the preferred cell surface ligand or ligands may depend on the targeted cell type.

In some embodiments, the transfection enhancers that are used in combination with the surface ligands disclose herein include, but are not limited to, the peptides or proteins selected from the group consisting of a collagen, a fibronectin, a lamin, a veronectin, a cadherin, a nidogen, a fibrinogen, a elastin, a bone asialoprotein, a osteopontin, a tenascin-C, Avadin, insulin, a transferrin, a epidermal growth factor, a fibroblast growth factor, a cell targeting antibody, a lactoferrin, an adenovirus penton base, a knob protein, a hexon protein, a vesicular stomatitis virus glycoprotein, a Semliki Forest Virus core protein, an influenza hemagglutinin, a hepatitis B core protein, an HIV Tat protein, a herpes simplex virus VP22 protein, a histone protein, an arginine rich cell permeability protein, a high mobility group protein, invasin protein, internalin protein, an endotoxin, a non-toxic diptheria toxin, a non-toxic shigella toxin, a melittin, a magainin, a gramicidin, a cecrophin, a defensin, a protegrin, a tachyplesin, a thionin, a indolicidin, a bactenecin, a drosomycin, an apidaecin, a cathelicidin, a bacteriacidal-permability-increasing protein, a nisin, a buforin, a fragment thereof, and a sequence selected from the group consisting of SEQ ID NOs:150-201, as set forth in Table 1, below, or in the sequence listings.

In some embodiments, the transfection enhancing agent is chloroquine, a lysosomotrophic compound or combinations thereof. In certain embodiments, the transfection enhancer agent comprises multimers of the same or different peptide enhancers, protein or protein fragments of transfection enhancers.

In some embodiments, the aforementioned peptides are optionally linked to a moiety selected from the group consisting of a nucleic acid binding moiety, a helper lipid, a cationic lipid, a cationic polymer, and a GPI anchor peptide.

In certain embodiments, the aforementioned peptides are optionally linked to a chemical moiety of Formula I,

or a pharmaceutically acceptable salt thereof, where

W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(NH₂)—CH₂—(CH₂)n-NH₂, n=0-6, y=0; or

W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(NH₂)—CH₂—(CH₂)n-OH, n=0-6, y=0; or

W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(OH)—CH₂—(CH₂)n-NH₂, n=0-6, y=0; or

W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(NH-iso-butyl)-CH₂—(CH₂)n-O-iso-butyl, n=0-6, y=0; or

W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(NH₂)—CH₂—(CH₂)n-C(═NH)—NH₂, n=0-6, y=0; or

W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(NH₂)—CH₂—(CH₂)n-His, n=0-6, y=0; or

W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)-spermine, y=0; or

W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═H, y=0; or

W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═CH₂(CH₂)_(m)—NH₂; m=1-6, y=0; or

W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═CH₂(CH₂)_(m)—NH—C(═O)-spermine; m=1-6, y=0; or

W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═CH₂(CH₂)_(m)—NH—(C═O)-amino acid side chain; m=1-6, y=0; or

W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═(CH₂)_(m)(CH—OH)(CH₂)_(m)—NH₂, y=0; or

W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═CH₂(CH₂)n-NH₂, y=0; or

W¹═H W²═CH₂—N(R³R⁴)CH₂—R⁵; R³═R⁴═CH₃; R⁵═H, y=0; or

W¹═H; W²═CH₂—O—P(═O)(OMe)-O—CH₂CH₂—NH—C(═O)-spermine, y=0; or

W¹═H; W²═CH₂—O—P(═O)(OMe)-O—CH₂CH₂—NH—C(═O)-amino acid side chain, y=0; or

W¹═H; W²═CH₂—O—P(═O)(OMe)-O—CH₂CH₂—N+(CH₃)₃Cl, y=0; or

W¹═H; W²═CH₂—O—P(═O)(O⁻)—O—CH₂CH₂—NH—C(═O)-spermine, y=0; or

Z═(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(NH₂)—CH₂—(CH₂)n-NH₂, n=0-6, q=1-3, y=1; or

Z═(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(NH₂)—CH₂—(CH₂)_(n)—OH, n=0-6, q=1-3, y=1; or

Z═(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(OH)—CH₂—(CH₂)_(n)—NH₂, n=0-6, q=1-3, y=1; or

Z═(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(NH-iso-butyl)-CH₂—(CH₂)_(n)—O-iso-butyl, n=0-6, y=1; or

Z═(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(NH₂)—CH₂—(CH₂)_(n)—C(═NH)—NH₂, n=0-6, q=1-3, y=1; or

Z═(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(NH₂)—CH₂—(CH₂)_(n)-His, n=0-6, q=1-3, y=1; or

Z═(CH₂)_(q)W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)-spermine, q=1-3, y=1; or

Z═(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═H, q=1-3, y=1; or

Z═(CH₂)_(q)W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═CH₂(CH₂)_(m)—NH₂; m=1-6, q=1-3, y=1; or

Z═(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═CH₂(CH₂)_(m)—NH—C(═O)-spermine; m=1-6, q=1-3, y=1; or

Z═(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═CH₂(CH₂)_(m)—NH—(C═O)-amino acid side chain; m=1-6, q=1-3, y=1; or

Z═(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═(CH₂)_(m)(CH—OH)(CH₂)_(m)—NH₂, q=1-3, y=1; or

Z═(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═CH₂(CH₂)n-NH₂, q=1-3, y=1; or

Z═(CH₂)_(q)—N(R³)—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³ ═CH₃, R⁴═—C(═O)—C(NH₂)—CH₂—(CH₂)n-NH₂, n=0-6, q=1-3, y=1; or

Z═(CH₂)_(p)—N(R³)—(CH₂)_(p), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³ ═CH₃, R⁴═—C(═O)—C(NH₂)—CH₂—(CH₂)n-OH, n=0-6, q=1-3, y=1; or

Z═(CH₂)_(q)—N(R³)—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³ ═CH₃, R⁴═—C(═O)—C(OH)—CH₂—(CH₂)n-NH₂, n=0-6, q=1-3, y=1; or

Z═(CH₂)_(q)—N(R³)—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³ ═CH₃, R⁴═—C(═O)—C(NH-iso-butyl)-CH₂—(CH₂)n-O-iso-butyl, n=0-6, y=1; or

Z═(CH₂)_(q)—N(R³)—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³ ═CH₃, R⁴═—C(═O)—C(NH₂)—CH₂—(CH₂)n-C(═NH)—NH₂, n=0-6, q=1-3, y=1; or

Z═(CH₂)_(q)—N(R³)—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³ ═CH₃, R⁴═—C(═O)—C(NH₂)—CH₂—(CH₂)n-His, n=0-6, q=1-3, y=1; or

Z═(CH₂)_(q)—N(R³)—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³ ═CH₃, R⁴═—C(═O)-spermine, q=1-3, y=1; or

Z═(CH₂)_(q)—N(R³)—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³ ═CH₃; R⁴═H, q=1-3, y=1; or

Z═(CH₂)_(q)—N(R³)—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³ ═CH₃; R⁴═CH₂(CH₂)_(m)—NH₂; m=1-6, q=1-3, y=1; or

Z═(CH₂)_(q)—N(R³)—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³ ═CH₃; R⁴═CH₂(CH₂)_(m)—NH—C(═O)-spermine; m=1-6, q=1-3, y=1; or

Z═(CH₂)_(q)—N(R³)—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³ ═CH₃; R⁴═CH₂(CH₂)_(m)—NH—(C═O)-amino acid side chain; m=1-6, q=1-3, y=1; or

Z═(CH₂)_(q)—N(R³)—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³ ═CH₃; R⁴═(CH₂)_(m)(CH—OH)(CH₂)_(m)—NH₂, q=1-3, y=1; or

Z═(CH₂)_(q)—N(R³)—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³ ═CH₃; R⁴═CH₂(CH₂)_(n)—NH₂, q=1-3, y=1; Z═(CH₂)_(q)—S—S—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(NH₂)—CH₂—(CH₂)_(n)—NH₂, n=0-6, q=1-3, y=1; or

Z═(CH₂)_(q)—S—S—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(NH₂)—CH₂—(CH₂)_(n)—OH, n=0-6, q=1-3, y=1; or

Z═(CH₂)_(q)—S—S—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(OH)—CH₂—(CH₂)_(n)—NH₂, n=0-6, q=1-3, y=1; or

Z═(CH₂)_(q)—S—S—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(NH-iso-butyl)-CH₂—(CH₂)_(n)—O-iso-butyl, n=0-6, y=1; or

Z═(CH₂)_(q)—S—S—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(NH₂)—CH₂—(CH₂)_(n)—C(═NH)—NH₂, n=0-6, q=1-3, y=1; or

Z═(CH₂)_(q)—S—S—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(NH₂)—CH₂—(CH₂)_(n)-His, n=0-6, q=1-3, y=1; or

Z═(CH₂)_(q)—S—S—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)-spermine, q=1-3, y=1; or

Z═(CH₂)_(q)—S—S—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═H, q=1-3, y=1; or

Z═(CH₂)_(q)—S—S—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═CH₂(CH₂)_(m)—NH₂; m=1-6, q=1-3, y=1; or

Z═(CH₂)_(q)—S—S—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═CH₂(CH₂)_(m)—NH—C(═O)-spermine; m=1-6, q=1-3, y=1; or

Z═(CH₂)_(q)—S—S—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═CH₂(CH₂)_(m)—NH—(C═O)-amino acid side chain; m=1-6, q=1-3, y=1; or

Z═(CH₂)_(q)—S—S—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═(CH₂)_(m)(CH—OH)(CH₂)_(m)—NH₂, q=1-3, y=1; or

Z═(CH₂)_(q)—S—S—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═CH₂(CH₂)_(n)—NH₂, q=1-3, y=1.

In some embodiments, the transfection agent comprises at least one or more cationic lipid from Formula I and may optionally also contain one or more neutral lipids; DOPE, DPhPE, saturated and unsaturated DPPE, saturated and unsaturated DMPE, cholesterol, DOPC, Lyso-PE (1-acyl-2-hydroxy-sn-glycero-3-phosphoethanolamine), Lyso-PC (1-acyl-3-hydroxy-sn-glycero-3-phosphocholine), 3-alkyloxy-2-hydroxy-1-acetamidopropane, 4-alkyloxy-3-hydroxy-1-acetamidopropane, 5-alkyloxy-4-hydroxy-1-acetamidopropane or 6-alkyloxy-5-hydroxy-1-acetamidopropane. In some embodiments, the alkyloxy in the above list is selected from the group consisting of myristyloxy, myristeleyloxy lauryloxy, palmityloxy, palmitoleyloxy, oleyloxy and streayloxy.

In other embodiment, the transfection agent comprises at least one or more cationic lipid of Formula I. In certain embodiments, the transfection agent optionally comprises one or more of cationic lipid, while in other embodiments, the agent optionally comprises one or more neutral lipids. In certain embodiments, the transfection agent comprises both one or more cationic lipid and one or more neutral lipid.

In some embodiments, the cationic lipid is selected from the group consisting of GeneIn™ (MTI-GlobalStem), TransfeX™ (ATCC), LipofectAmine™ 2000, LipofectAmine 3000, LipofectAmine™, Lipofectin®, DMRIE-C, CellFectin® (Invitrogen), Oligofectamine® (Invitrogen), LipofectAce® (Invitrogen), Fugene® (Promega), Fugene® HD (Promega), Transfectam® (Promega), Tfx-10® (Promega), Tfx-20® (Promega), Tfx-50® (Promega), DNA-In (MTI-GlobalStem), Transfectin™ (BioRad, Hercules, Calif.), SilentFect™ (Bio-Rad), Effectene® (Qiagen, Valencia, Calif.), DC-chol (Avanti Polar Lipids), GenePorter® (Gene Therapy Systems, San Diego, Calif.), DharmaFect 1® (Dharmacon, Lafayette, Colo.), DharmaFect 2® (Dharmacon), DharmaFect 3® (Dharmacon), DharmaFect 4® (Dharmacon), Escort™ III (Sigma, St. Louis, Mo.), Escort™ IV (Sigma), ViaFect™ (Promega), DOTMA, DOTAP, DMRIE, DC-Chol, DDAB, DOSPA, DOSPER, DOGS, TMTPS, TMTOS, TMTLS, TMTMS, TMDOS, N-1-dimethyl-N-1-(2,3-diaoleoyloxypropyl)-2-hydroxypropane-1,3-diamine, N-1-dimethyl-N-1-(2,3-diamyristyloxypropyl)-2-hydroxypropane-1,3-diamine, N-1-dimethyl-N-1-(2,3-diapalmityloxypropyl)-2-hydroxypropane-1,3-diamine, N-1-dimethyl-N-1-(2,3-diaoleoyl-oxypropyl)-2-(3-amino-2-hydroxypropyloxy)propane-1,3-diamine, N-1-dimethyl-N-1-(2,3-diamyristyloxypropyl)-2-(3-amino-2-hydroxypropyloxy)propane-1,3-diamine, N-1-dimethyl-N-1-(2,3-diapalmityloxypropyl)-2-(3-amino-2-hydroxypropyloxy)propane-1,3-diamine, L-spermine-5-carboxyl-3-(DL-1,2-dipalmitoyl-dimethylaminopropyl-β-hydroxyethylamine, 3,5-(N,N-di-lysyl)-diaminobenzoyl-glycyl-3-(DL-1,2-dipalmitoyl-di-methylaminopropyl-p-hydroxyethylamine), L-Lysine-bis(O,O′-oleoyl-p-hydroxyethyl)-amide dihydrochloride, L-Lysine-bis-(O,O′-palmitoyl-p-hydroxyethyl)amide dihydrochloride, 1,4-bis[(3-(3-aminopropyl)-alkylamino)-2-hydroxypropyl)piperazine, L-Lysine-bis-(O,O′-myristoyl-p-hydroxyethyl)amide dihydrochloride, L-Ornithine-bis-(O,O′-myristoyl-p-hydroxyethyl)amide dihydrochloride, L-Omithine-bis-(O,O′-oleoyl-O-hydroxyethyl)amide dihydrochloride, 1,4-bis[(3-(3-aminopropyl)-oleylamino)-2-hydroxypropyl]piperazine, L-Ornithine-bis-(O,O′-palmitoyl-p-hydroxyethyl)amide dihydrochloride, 1,4,-bis[(3-amino-2-hydroxypropyl)-oleylamino]-butane-2,3-diol, 1,4,-bis[(3-amino-2-hydroxypropyl)-palmitylamino]-butane-2,3-diol, 1,4,-bis[(3-amino-2-hydroxypropyl)-myristylamino]-butane-2,3-diol, 1,4-bis[(3-oleylamino)propyl]piperaz-me, L-Arginine-bis-(O,O′-oleoyl-p-hydroxyethyl)amide dihydrochloride, bis[(3-(3-aminopropyl)-myristylamino)2-hydroxypropyl]piperazine, L-Arginine-bis-(O,O′-palmitoyl-p-hydroxyethyl)amide dihydrochloride, L-Serine-bis-(O,O′-oleoyl-β-hydroxyethyl)amide dihydrochloride, 1,4-bis[(3-(3-aminopropyl)-palmitylamino)-2-hydroxypropyl]piperazine, Glycine-bis-(O,O′-palmitoyl-p-hydroxyethyl)amide dihydrochloride, Sarcosine-bis-(O,O′-palmitoyl-β-hydroxyethyl)amide dihydrochloride, L-Histidine-bis-(O,O′-palmitoyl-β-hydroxyethyl)amide dihydrochloride, cholesteryl-3β-carboxyl-amidoethylenetrimethylammonium iodide, 1,4-bis[(3-myristylamino)propyl]-piperazine, 1-dimethylamino-3-trimethylammonio-DL-2-propyl-cholesteryl carboxylate iodide, cholesteryl-3β-carboxyamidoethyleneamine, cholesteryl-3β-oxysuccinamidoethyl-enetrimethylammonium iodide, 1-dimethylamino-3-trimethylammonio-DL-2-propyl-cholesteryl-3β-oxysuccinate iodide, 2-[(2-trimethylammonio)-ethylmethylamino] ethyl-cholesteryl-3β-oxysuccinate iodide, 3β[N—(N′,N′-dimethylaminoethane)carbamoyl]-cholesterol, and 3β-[N-(polyethyleneimine)-carbamoyl] cholesterol,1,4-bis[(3-palmitylamino)propyl]piperazine, L-Ornithylglycyl-N-(1-heptadecyloctadecyl)glycin-amide, N²,N⁵-Bis(3-aminopropyl)-L-ornithylglycyl-N-(1-heptadecyloctadecyl)glycin-amide, 1,4-bis[(3-(3-amino-2-hydroxypropyl)-alkylamino)-2-hydroxypropyl]piperazine N²—[N²,N⁵-Bis(3-aminopropyl)-L-ornithyl]-N,N-dioctadecyl-L-glutamine,N²—[N²,N⁵-Bis(aminopropyl)-L-ornithyl]-N—N-dioctadecyl-L-α-glutamine, 1,4-bis[(3-(3-amino-2-hydroxypropyl)-oleylamino)2-hydroxypropyl]piperazine, N²—[N²,N⁵-Bis(aminopropyl)-L-omithyl]-N—N-dioctadecyl-L-α-asparagine, N—[N²—[N²,N⁵-Bis[(1,1-dimethylethoxy)-carbonyl]-N²,N⁵-bis[3-[(1,1-dimethylethoxy)carbonyl]aminopropyl]-L-ornithyl-N—N-dioctadecyl-L-glutaminyl]-L-glutamic acid, N²—[N²,N⁵-Bis(3-aminopropyl)-L-omithyl]-N,N-diolyl-L-glutamine, N²—[N²,N⁵-Bis(aminopropyl)-L-omithyl]-N—N-dioleyl-L-α-glutamine,4-bis[(3-(3-amino-2-hydoxypropyl)-myristylamino)-2-hydroxypropyl]piperazine, N²—[N²,N⁵-Bis(aminopropyl)-L-ornithyl]-N—N-dioleyl-L-α-asparagine, N—[N²—[N²,N⁵-Bis[(1,1-dimethylethoxy)carbonyl]-N²,N⁵-bis[3-[(1,1-dimethylethoxy)carbonyl]-aminopropyl]-L-omithyl-N—N-dioleyl-L-glutaminyl]-L-glutamic acid, 1,4-bis[(3-(3-aminopropyl)-oleylamino)propyl]piperazine, N²—[N²,N⁵-Bis(3-aminopropyl)-L-omithyl]-N,N-dipalmityl-L-glutamine,N²—[N²,N⁵-Bis(aminopropyl)-L-ornithyl]-N—N-dipalmityl-L-α-glutamine, N²—[N²,N⁵-Bis(aminopropyl)-L-ornithyl]-N—N-dipalmityl-L-α-asparagine, N—[N²—[N²,N⁵-Bis[(1,1-dimethylethoxy)carbonyl]-N²,N⁵-bis[3-[(1,1-dimethylethoxy)-carbonyl]aminopropyl]-L-ornithyl-N—N-dipalmityl-L-glutaminyl]-L-glutamic acid, N²—[N²,N⁵-Bis(3-aminopropyl)-L-ornithyl]-N,N-dimyristyl-L-glutamine, N²—[N²,N⁵-Bis-(aminopropyl)-L-ornithyl]-N—N-dimyristyl-L-α-glutamine, N²—[N²,N⁵-Bis(aminopropyl)-L-ornithyl]-N—N-dimyristyl-L-α-asparagine, 1,4-bis[(3-(3-amino-2-hydroxypropyl)-palmitylamino)-2-hydroxypropyl]piperazine, N—[N²—[N²,N⁵-Bis[(1,1-dimethylethoxy)-carbonyl]-N²,N⁵-bis[3-[(1,1-dimethylethoxy)carbonyl]aminopropyl]-L-ornithyl-N—N-dimyristyl-L-glutaminyl]-L-glutamic acid, 1,4-bis[(3-(3-aminopropyl)-myristylamino)-propyl]piperazine, N²—[N²,N⁵-Bis(3-aminopropyl)-L-ornithyl]-N,N-dilaureyl-L-glutamine, N²—[N²,N⁵-Bis(aminopropyl)-L-omithyl]-N—N-dilaureyl-L-α-glutamine, N²—[N²,N⁵-Bis(aminopropyl)-L-omithyl]-N—N-dilaureyl-L-α-asparagine, N—[N2-[N2,N⁵-Bis[(1,1-dimethylethoxy)carbonyl]-N²,N⁵-bis[3-[(1,1-dimethylethoxy)carbonyl]amino-propyl]-L-ornithyl-N—N-dilaureyl-L-glutaminyl]-L-glutamic acid, 3-[N′,N″-bis(2-tert-butyloxycarbonylaminoethyl)guanidino]-N,N-dioctadec-9-enylpropionamide, 3-[N′,N″-bis(2-tertbutyloxycarbonylaminoethyl)guanidino]-N,N-dipalmitylpropionamide, 3-[N′,N″-bis(2-tertbutyloxycarbonylaminoethyl)guanidino]-N,N-dimyristylpropionamide, 1,4-bis[(3-(3-aminopropyl)-palmitylamino)propyl]piperazine, 1,4-bis[(3-(3-amino-2-hydroxypropyl)-oleylamino)propyl]piperazine, N,N-(2-hydroxy-3-aminopropyl)-N-2-hydroxypropyl-3-N,N-diolylaminopropane, N,N-(2-hydroxy-3-aminopropyl)-N-2-hydroxypropyl-3-N,N-dipalmitylaminopropane, N,N-(2-hydroxy-3-aminopropyl)-N-2-hydroxypropyl-3-N,N-dimyristylaminopropane, 1,4-bis[(3-(3-amino-2-hydoxypropyl)-myristylamino)propyl]piperazine, [(3-aminopropyl)-bis-(2-tetradecyloxyethyl)]methyl ammonium bromide, [(3-aminopropyl)-bis-(2-oleyloxyethyl)]methyl ammonium bromide, [(3-aminopropyl)-bis-(2-palmityloxyethyl)]methyl ammonium bromide, Oleoyl-2-hydroxy-3-N,N-dimethyamino propane, 2-didecanoyl-1-N,N-dimethylaminopropane, palmitoyl-2-hydroxy-3-N,N-dimethyamino propane, 1,2-dipalmitoyl-1-N,N-dimethylaminopropane, myristoyl-2-hydroxy-3-N,N-dimethyamino propane, 1,2-dimyristoyl-1-N,N-dimethylaminopropane, (3-Amino-propyl)->4-(3-amino-propyl-amino)-4-tetradecylcarbamoyl-butylcarbamic acid cholesteryl ester, (3-Amino-propyl)->4-(3-amino-propylamino-4-carbamoylbutylcarbamic acid cholesteryl ester, (3-Amino-propyl)->4-(3-amino-propylamino)-4-(2-dimethylamino-ethylcarbamoyl)-butylcarbamic acid cholesteryl ester, Spermine-5-carboxyglycine (N′-stearyl-N′-oleyl) amide tetratrifluoroacetic acid salt, Spermine-5-carboxyglycine (N′-stearyl-N′-elaidyl) amide tetratrifluoroacetic acid salt, Agmatinyl carboxycholesterol acetic acid salt, Spermine-5-carboxy-β-alanine cholesteryl ester tetratrifluoroacetic acid salt, 2,6-Diaminohexanoeyl β-alanine cholesteryl ester bistrifluoroacetic acid salt, 2,4-Diaminobutyroyl β-alanine cholesteryl ester bistrifluoroacetic acid salt, N,N-Bis (3-aminopropyl)-3-aminopropionyl β-alanine cholesteryl ester tristrifluoroacetic acid salt., [N,N-Bis(2-hydroxyethyl)-2-aminoethyl]aminocarboxy cholesteryl ester, Stearyl carnitine ester, Palmityl carnitine ester, Myristyl carnitine ester, Stearyl stearoyl carnitine ester chloride salt, L-Stearyl Stearoyl Carnitine Ester, Stearyl oleoyl carnitine ester chloride, Palmityl palmitoyl carnitine ester chloride, Myristyl myristoyl carnitine ester chloride, L-Myristyl myristoyl carnitine ester chloride, 1,4-bis[(3-(3-amino-2-hydroxypropyl)-palmitylamino)-propyl]piperazine, N-(3-aminopropyl)-N,N′-bis-(dodecyloxyethyl)-piperazinium bromide, N-(3-aminopropyl)-N,N′-bis-(oleyloxyethyl)-piperazinium bromide, N-(3-aminopropyl)-N,N′-bis-(palmityloxyethyl)-piperazinium bromide, N-(3-aminopropyl)-N,N′-bis-(myristyloxyethyl)-piperazinium bromide, N-(3-aminopropyl)-N′-methyl-N,N′-(bis-2-dodecyloxyethyl)-piperazinium bromide, N-(3-aminopropyl)-N′-methyl-N,N′-(bis-2-oleyloxyethyl)-piperazinium bromide, N-(3-aminopropyl)-N′-methyl-N,N′-(bis-2-palmityloxyethyl)-piperazinium bromide, N-(3-aminopropyl)-N′-methyl-N,N′-(bis-2-myristyloxyethyl)-piperazinium bromide, 1,4-bis[(3-(3-aminopropyl)-oleylamino)-2-hydroxy-propyl]piperazine, 1,4-bis[(3-(3-aminopropyl)-myristylamino)-2-hydroxy-propyl]piperazine, or 1,4-bis[(3-(3-aminopropyl)-palmitylamino)-2-hydroxy-propyl]piperazine, 3-alkyloxy-2-hydroxy-1-histidylamidopropane, 3-alkyloxy-2-hydroxy-1-aminopropane, 4-alkyloxy-3-hydroxy-1-histidylamidopropane, 4-alkyloxy-3-hydroxy-1-aminopropane, 5-alkyloxy-4-hydroxy-1-histidylamidopropane, 5-alkyloxy-4-hydroxy-1-aminopropane, 6-alkyloxy-5-hydroxy-1-histidylamidopropane, 6-alkyloxy-4-hydroxy-1-aminopropane; 2,3-dialkoxy-1,4-bis(N-methyl-N-carboxyspermineamido)-aminobutane, 2,3-dialkoxy-1,4-bis(N-methyl-N-histidinylamido)aminobutane, 2,3-dialkoxy-1,4-bis(N-methyl-N-arginylamido)aminobutane, 2,3-dialkoxy-1,4-bis(N-methyl-N-lysinylamido)aminobutane, 2,3-dialkoxy-1,4-bis(N-methyl-N′-omithinyl-amido)aminobutane, 2,3-dialkoxy-1,4-bis(N-methyl-N-serinylamido)aminobutane, 2,3-dialkoxy-1,4-bis(N-methyl-N-homoerinylamido)aminobutane, 2,3-dialkoxy-1,4-bis(N-methyl-N-(diaminobutanyl)amido)aminobutane, 2,3-dialkoxy-1,4-bis(N-methyl-N-(di-aminopropyl)amido)aminobutane, 2,3-dialkoxy-1,4-bis(N-methyl-N-(2-hydroxylpropyl-amine))aminobutane, 2,3-dialkoxy-1,4-bis(N-methyl-N-(2-diaminopropyl))aminobutane, 2,3-dialkoxy-1,4- and bis(N-methyl-N-propylamine)aminobutane. The alkoxy in the above list may be myristyloxy, myristeleyloxy lauryloxy, palmityloxy, palmitoleyloxy, oleyloxy and streaylox.

When the composition contains a neutral lipid, that lipid a saturated or unsaturated, or mixed acyl phospatidyl ethanol mine (PE) or phospahtidyl choline (PC), for example, DOPE, DPhPE, saturated and unsaturated DPPE, saturated and unsaturated DMPE, cholesterol, DOPC, Lyso-PE (1-acyl-2-hydroxy-sn-glycero-3-phosphoethanolamine), Lyso-PC (1-acyl-3-hydroxy-sn-glycero-3-phosphocholine), 3-alkyloxy-2-hydroxy-1-acetamidopropane, 4-alkyloxy-3-hydroxy-1-acetamidopropane, 5-alkyloxy-4-hydroxy-1-acetamidopropane or 6-alkyloxy-5-hydroxy-1-acetamidopropane. The alkyloxy in the above list may be myristyloxy, myristeleyloxy lauryloxy, palmityloxy, palmitoleyloxy, oleyloxy or streayloxy. In some embodiment, the transfection agent The composition may contain more than one of these neutral lipids.

In other embodiments the transfection agent comprises at least one polyamine moiety. Suitable polyamines include dense star dendrimers, PAMAM dendrimers, NH₃ core dendrimers, ethylenediamine core dendrimers, dendrimers of generation 5 or higher, dendrimers with substituted groups, dendrimers having one or more amino acids, grafted dendrimers, activated dendrimers, polyethylenimine, and polyethylenimine conjugates, polycationic peptides such as polylysine, polyorinthine, polyhistidine, polyarginine,

In specific embodiments, the cell surface ligand containing adhesion peptide sequences is covalently linked to the transfection agents, the cationic lipid, the neutral lipid, helper lipid, a chemical group that associates with lipids or liposomes, and/or the polyamine.

In other embodiments, cell surface ligand containing adhesion peptide sequences is conjugated to a nucleic acid binding group. In some of these embodiments, the nucleic acid binding group is linked to a polyamine or peptide nucleic acid. The polyamine optionally comprises at least one spermine moiety.

Suitable cell surface ligands containing adhesion peptide sequences that are derived from cell adhesion proteins include, but are not limited to, a sequence selected from the group consisting of SEQ ID NOs:202-503, as set forth in Table 1, below, or in the sequence listings.

In some embodiments, the peptides of SEQ ID NOs:202-503 are optionally linked to a nucleic acid binding moiety, a helper lipid, a cationic lipid, a cationic polymer, a GPI anchor peptide or other chemical moieties that associate with transfection complexes.

In some embodiments, the peptides of SEQ ID NOs:202-500 are used with other surface ligands, such as antibodies, antibody fragments, single chain antibodies, aptemers, or peptides from phage display. In certain embodiments, these surface ligands are optionally attached to nucleic acid binding moieties, to lipids or lipid associating moieties.

In particular embodiments, the transfection agent comprises at least one cationic lipid, and optionally also contains in various combinations with one or more neutral and/or helper lipids, targeting moieties, cell penetration agent, fusion agents, and lysomotropic agents.

In some embodiments, the presently disclosed complexes comprise one more agents selected from the group consisting of fusogenic agents, nuclear localization sequences, cell penetration agent, transport peptides, receptor-ligand or cell adhesion peptides.

It is to be understood that while some peptides are disclosed herein in the context of one particular use, all of the peptides presently disclosed can be used in other uses as well. Thus, by way of example only, the peptides of SEQ ID NOs:1-41 are disclosed to be nuclear localization peptides. However, these peptides can be used as a nucleic acid binding peptide, a nucleic acid condensing peptide, a transfection enhancer.

In another aspect, disclosed herein are pharmaceutical compositions containing a complex as described herein, and a pharmaceutically acceptable carrier.

In another aspect, disclosed herein are methods of transfecting a cell, by contacting a cell with a complex as described herein. In some embodiments, the cell is selected from the group consisting of a primary cell culture, a passaged cell culture, suspension cell line and an attached cell line. Suitable cells include all human cell lines and all animal cell lines. In some embodiments, the cell is a stem cell, while in other embodiments, the cell is a neuron.

In one method, a nucleic acid, protein or, peptide, or pharmaceutical is contacted with a cell surface ligand containing adhesion peptide sequences capable associating with nucleic acid, protein, peptide or pharmaceutical and the resulting mixture is added to a transfection agent then contacted to cells.

In one embodiment of the transfection methods, cell surface ligand containing adhesion peptide sequences are contacted with a transfection agent capable of associating with a nucleic acid, a protein, a peptide or a pharmaceutical composition, followed by addition of a nucleic acid, a protein, peptide or pharmaceutical then contacted to cells.

In another method, cell surface ligand containing adhesion peptide sequences linked to a nucleic acid binding moiety is contacted with transfection agent capable of associating with nucleic acid, protein, peptide or pharmaceutical followed by addition of a nucleic acid, protein, peptide or pharmaceutical then contacted to cells

In another method, cell surface ligand containing adhesion peptide sequences is contacted with transfection agent followed by addition of a fusion agent and then contacted with a nucleic acid, protein, peptide or pharmaceutical then contacted to cells

In another method, cell surface ligand containing adhesion peptide sequences linked to a nucleic acid binding moiety is contacted with transfection agent followed by addition of a fusion agent and then contacted with a nucleic acid, protein, peptide or pharmaceutical then contacted to cells

In another method, cell surface ligand containing adhesion peptide sequences is contacted with a fusion agent followed by addition of a transfection agent and then contacted with a nucleic acid, protein, peptide or pharmaceutical then contacted to cells.

In another method, cell surface ligand containing adhesion peptide sequences linked to a nucleic acid binding moiety is contacted with a fusion agent followed by addition of a transfection agent and then contacted with a nucleic acid, protein, peptide or pharmaceutical then contacted to cells.

In another method, a transfection complex is contacted with a nucleic acid, protein or, peptide then contacted with cell surface ligand containing adhesion peptide sequences and then contacted to cells.

Those skilled in the art understand that concentrations of the various components (cationic lipid, helper lipid, cell surface ligand, fusogenic reagent, nuclear ligand, cationic polymer, condensing agent, cell penetration, lysomotrophic agent, and transfection enhancers are optimized according to the cell to be transfected or the in vivo application. In some embodiments, the concentration of each component ranges from 0.01 to 20 mg/mL, depending on solubility and formulation solvent.

In some embodiments, the peptides disclosed herein are suitable for use in the disclosed transfection enhancers to enhance transfection into HeLa cells, HuVec cells, iPS cells, NL-1 cells, C2C12 cells, human fibroblast cells, Jurkat cells, rat cortical neurons, THP-1 cells, and human skeletal muscle cells, among others.

In some embodiments, the peptide useful to enhance the transfection of HeLa cells is selected from the group consisting of SEQ ID NOs:107, 205, 216, 218, 219, 220, 224, 226, 229, 230, 234, 236, 236, 237, 238, 239, 256, 268, 323, 326, 327, 328, 332, 335, 336, 338, 341, 342, 343, 344, 345, 347, 348, 349, 350, 351, 352, 353, 354, 355, 357, 358, 359, 360, 361, 363, 365, 367, 369, 371, 373, 375, 377, 379, 381, 383, 450, 452, 454, and 503. In some of these embodiments, the peptide useful to enhance the transfection of HeLa cells is selected from the group consisting of SEQ ID NOs:205, 237, 268, 326, 328, 335, 336, 342, 347, 348, 352, 353, 355, 357, 358, 365, 367, 377, 379, 381, 450, 454, and 503.

In some embodiments, the peptide useful to enhance the transfection of HuVec cells is selected from the group consisting of SEQ ID NOs:205, 216, 218, 219, 220, 224, 226, 229, 230, 234, 236, 236, 237, 238, 239, 256, 268, 323, 326, 327, 328, 332, 335 336, 338, 341, 342, 343, 344, 345, 347, 348, 349, 350, 351, 352, 353, 354, 355, 357, 358, 359, 360, 361, 363, 365, 367, 369, 371, 373, 375, 377, 379, 381, 383, 450, 452, 454, and 503. In some of these embodiments, the peptide useful to enhance the transfection of HuVec cells is selected from the group consisting of SEQ ID NOs:236, 358, and 373.

In some embodiments, the peptide useful to enhance the transfection of NL-1 iPS cells is selected from the group consisting of SEQ ID NOs:107, 205, 216, 218, 219, 220, 224, 226, 229, 230, 234, 236, 236, 237, 238, 239, 256, 268, 323, 326, 327, 328, 332, 335, 336, 338, 341, 342, 343, 344, 345, 347, 348, 349, 350, 351, 352, 353, 354, 355, 357, 358, 359, 360, 361, 363, 365, 367, 369, 371, 373, 375, 377, 379, 381, 383, 450, 452, 454, and 503. In some of these embodiments, the peptide useful to enhance the transfection of NL-1 iPS cells is selected from the group consisting of SEQ ID NOs:216, 224, 226, 236, 236, 323, 327, 341, 343, 347, 348, 349, 350, 351, 354, 358, 360, 373, 383, 450, 454, and 503.

In some embodiments, the peptide useful to enhance the transfection of C2C12 cells is selected from the group consisting of SEQ ID NOs:205, 216, 218, 219, 220, 224, 226, 229, 230, 234, 236, 236, 237, 238, 239, 256, 268, 323, 326, 327, 328, 332, 335, 336, 338, 341, 342, 343, 344, 345, 347, 348, 350, 351, 352, 353, 354, 355, 357, 358, 359, 360, 361, 363, 365, 367, 369, 371, 373, 375, 377, 379, 381, 383, 450, 452, 454, 501, 502, and 503. In some of these embodiments, the peptide useful to enhance the transfection of C2C12 cells is selected from the group consisting of SEQ ID NOs:218, 230, 237, 239, 256, 323, 326, 328, 335, 336, 342, 343, 345, 347, 348, 352, 357, 359, 367, 375, 379, 381, 450, 452, 454, 501, 502, and 503.

In some embodiments, the peptide useful to enhance the transfection of human fibroblast cells is selected from the group consisting of SEQ ID NOs:205, 216, 218, 219, 220, 224, 226, 229, 230, 234, 236, 236, 237, 238, 239, 256, 268, 323, 326, 327, 328, 332, 335, 336, 338, 341, 342, 343, 344, 345, 347, 348, 349, 350, 351, 352, 353, 354, 355, 357, 358, 359, 360, 361, 363, 365, 367, 369, 371, 373, 375, 377, 379, 381, 383, 450, 452, 454, 501, and 503. In some of these embodiments, the peptide useful to enhance the transfection of human fibroblast cells is selected from the group consisting of SEQ ID NOs:205, 218, 219, 229, 230, 335, 336, 342, 344, 348, 349, 350, 351, 353, 355, 357, 361, 367, 369, 375, 379, 381, 450, 454, 501, and 503.

In some embodiments, the peptide useful to enhance the transfection of Jurkat cells is selected from the group consisting of SEQ ID NOs:205, 216, 218, 219, 220, 224, 226, 229, 230, 234, 236, 236, 237, 238, 239, 256, 268, 323, 326, 327, 328, 332, 335, 336, 338, 341, 342, 343, 344, 345, 347, 348, 349, 350, 351, 352, 353, 354, 355, 357, 358, 359, 360, 361, 363, 365, 367, 369, 371, 373, 375, 377, 379, 381, 383, 450, 452, 454, 501, and 503. In some of these embodiments, the peptide useful to enhance the transfection of Jurkat cells is selected from the group consisting of SEQ ID NOs:218, 349, and 358.

In some embodiments, the peptide useful to enhance the transfection of rat cortical neuron cells is selected from the group consisting of SEQ ID NOs: 220, 236, 238, 323, 327, 336, 338, 341, 343, 347, 348, 350, 351, 352, 354, 367, 369, 373, 375, 377, and 454.

In some embodiments, the peptide useful to enhance the transfection of THP-1 cells is selected from the group consisting of SEQ ID NOs:219, 229, 230, 239, 323, 328, 332, 341, 343, 350, 351, 357, 358, 375, 450, and 454.

In some embodiments, the peptide useful to enhance the transfection of human skeletal muscle cells is selected from the group consisting of SEQ ID NOs: 218, 219, 230, 328, 336, 344, 350, 351, 353, 355, 365, and 375.

In some embodiments combination of different surface ligands that have preference for a given cell types are mixed together to target multiple cell types in a single formulation.

In another aspect, disclosed herein are kits containing a transfection agent and a peptide or protein or a modified peptide or modified protein with surface ligands, as described herein. In some embodiments, the kit further comprises instructions for the preparation and the use of the transfection complexes. In certain embodiments, the kit further comprises separate compartments for the various components. Certain

EXAMPLES Example 1

Cells were plated to so that on the day of transfection the cells were 60-70% confluent in 96 well tissue culture plates. A DOMTA/DOPE Lipid solution (1:1 molar ratio) at 2 mg/mL in water were mixed with an equal volume of surface ligand peptides that had the nucleic acid binding moiety RRRRRRRRRRRR (SEQ ID NO:109) covalently linked to the n terminus of each peptide during peptide synthesis. Peptides were at 2 mg/mL in water. The DOTMA/DOPE and the surface ligand peptide solution the transfection reagent was diluted 1 to 1 (v/v) in water. DOMTA/DOPE/PEPTIDE solutions were added to 0.1 mL of a plasmid DNA solution (EF1Alpha eGFP plasmid) at 5 μg/mL in OptiMEM. Lipofectamine 2000 was obtained from Life Technologies.

All solutions were at room temperature. A volume of 0.2 mL of a 5 g/mL solution of DNA was aliquoted into each well of a non-tissue cultured treated plate. 4.0 μL of transfection reagents were added to DNA solutions respectively. The transfection reagent and DNA solution was mixed by pipetting up and down twice. Transfection complexes were formed for 10 minutes. After 10 minutes, 0.01 or 0.02 mL of the transfection complex was added to cells. HuVEC, HeLa, human adult keratinocytes, human primary adult fibroblast, and rat cortical neurons all respectively received 0.01 mL of the transfection complex. Human skeletal muscle cells, mouse C2C12 cells, Jurkat, and THP-1 cells received 0.02 mL of the transfection complex. Cells were incubated for 42 hours at 37° C. at 5% CO2. Plates were read on a fluorescent plate reader. Cells were also examined visually under a microscope to assess the extent of transfection (in terms of the percent of cells transfected) with a fluorescent microscope. Other modes of analysis, for example quantification with B-galactosidase or luciferase reports plasmids can also be used. If the plate reader did not show a sufficient signal to noise ratio, then plates were scored for cells transfected and those peptides that show increase over DOTMA alone were noted. Not all surface ligands increased transfection efficiency even though they were suggested to be used to attach cell to tissue culture plates. Surface ligand that caused increase expression of GFP over the lipid DOTMA with no surface ligand were considered to enhance transfection or had higher % cells transfected were considered to enhance transfection. Peptides that gave greater than 2 fold enhancement are noted in bold and could be further optimized by adding different transfection enhancers or could be used with different cationic lipids or polymers.

Tables 2-7, below, provide the results of the transfection enhancements with the various cell types, while Table 8 lists the peptides that were determined by visual inspection to enhance the transfection of the denoted cell lines over the lipid DOTMA.

The following sequences increased transfection expression and the % cells transfected over the no peptide control on some examined cell types: SEQ ID NOs: 205, 216, 218, 219, 220, 226, 229,230, 236, 237, 238, 239, 256, 268, 323, 326, 327, 328, 332, 336, 338, 341, 342, 343, 344, 345, 347, 348, 349, 350, 351, 352, 353, 354, 355, 357, 358, 359, 360, 361, 365, 367, 369, 373, 375, 377, 379, 381, 393, 450, 452, 454, 501, and 503.

Various DOTMA/peptide transfection reagents that showed enhanced transfection efficiency over DOTMA alone were further formulated with the fusogenic peptide (SEQ ID NO:72). The fusogenic peptide was added to the DOMTA/peptide formulation to achieve a final concentration of 0.1 mg/mL to see if transfection reagents were further enhanced by the addition of a fusogenic peptide and could provide higher transfection efficiency into HeLa cells and expression than the commercially available Lipofectamine 2000. The results are shown in Table 9.

The following Table 1 lists the peptide sequences that are referenced herein.

TABLE 1 SEQ ID NO Sequence 1 GYSTPPKKKRKVEDP 2 GYSTPPKTRRRP 3 GYSTPGRKKR 4 GYSTPRRNRRRRW 5 PDEVKRKKKPPTSYG 6 PRRRTKPPTSYG 7 RKKRGPTSYG 8 WRRRRNRRPTSYG 9 GYGPPKKKRKVEAPYKA 10 PAAKRVKLD 11 RQRRNELKRSP 12 KRPAATKKAGQAKKKK 13 VRKKRKTEEESPLKDKDAKKSKQE 14 RLRRDAGGRGGVYEHLGGAPRRRK 15 KRKGDEVDGVDECAKKSKK 16 NQSSNFGPMKGGNFGGRSSGPYGGGGQYFAKPRNQGGY 17 GGKRTADGSEFESPKKARKVEAYPKAW 18 GGKRTADGSEFESPKKKRAVEAYPKAW 19 GGKRTADGSEFESPKKKAKVEAYPKAW 20 GGKRTADGSEFESPKKKRKVEAPYKAWK 21 GGKRTADGSEFESPKKKRKVEYKAWK 22 GYGPAAKRVKLDEAYPKAWK 23 GGKRTADGSEFEPAAKRVKLDEAYPKAWK 24 GTGPKKKRKVGGGGYGPKKKRLVG 25 KRPAATKKAGQAKKKKLEAYPKAWK 26 ATKGTKRSYEQMETGE 27 GKWERKPIRCAS 28 GYGKRTADSQHSTPPKKKRKVEAPYKAWK 29 KRTADSQHSTPPKKKRKVEAPYKAWK 30 GYGPPKKKRKVEAPYKAWKWAKYPAMRRAHHRRRRASHRRRTTT GT 31 GYGPPKKKRKVEAPYKAWKRGARRYSKMKRRRRRVARRHRRRP 32 FWGYGYGPPKKKRKVEAPYKAWK 33 GKPSSDDEATADSQHSTPPKKKERKVED 34 GKPTADDQHSTPPKKKRKVED 35 GGKRTADGSEFESPKKARKVEAYPKAK 36 EKIRLRPGRKKRYRLKHL 37 PEGTRQARRNRRRRWRKR 38 PEGTRQPRRNRRRRWRKR 39 GVKRSYGAARGDDRRRPNVVAPYKAW 40 KSVPNRTRTYIKLKRLRFKGAPYKAW 41 EMRRRREEEGLQLRKQKREEQLFKRRN 42 FEAALAEALAEALA 43 Ac-LARLLPRLLARL-NHCH₃ 44 GLLEELLELLEELWEELLEG 45 GWEGLIEGIEGGWEGLIEG 46 GLFEALAEFIEGGWEGLIEG 47 GLFEALLELLESLWELLLEA 48 GGYCLEKWMIVASELKCFGNTA 49 GGYCLTRWMLIEAELKCFGNTAV 50 WEAALAEALAEALAEHLAEALAEALEALAA 51 GLFGAIAGFIENGWEGMIDGWYG 52 GIGAVLKVLTTGLPALISWIKRKRQQ 53 GRKKRRQRRRPPQ 54 RQIKIWFQNRRMKWKK 55 GWTLNSAGYLLGKINLKALAALAKKIL 56 WEAKLAKALAKALAKHLAKALAKALKACEA 57 GLFKALLKLLKSLWKLLLKA 58 GLFRALLRLLRSLWRLLLRA 59 GLFEALLELLESLYELLLEA 60 GLFEALEELWEA 61 GLFLLEEWLE 62 GLFLLEEWLEK 63 GLFEALLELLESLWELLLEAK 64 SucGLFKLLEEWLE 65 SucGLFKLLEEWLEK 66 GLFEAIAEFIEGGWEGLIEG 67 GLFKAIAKFIKGGWKGLIKG 68 IRFKKTKLIASIAMALC 69 ALAGTIIAGASLTFQVLDKVlEELGKVSRK 70 GLFEAIEGFIENGWEGMIDGWYG 71 GYICRRARGDNPDDRCT 72 GLFEAIAEFIEGGWEGLIEGCA 73 GLFHAIAHFIHGGWHGLIHGWWYG 74 RRRQRRKKRGGDIMGEWGNEIFGAIAGFLG 75 GLFEAIADFIENGWEGMIDGGG 76 ALAGTIIAGASLTFQVLDKVlEELGKVSRKK 77 IRFKKTKLIASIAMA 78 LCL 79 KKIMLLLMTLLLVSLPLAQEQ 80 GLFEALLELLESLWELLLEAWYG 81 LEL 82 LLELELLELELLLELELLELELLLEL 83 GLFEALLELLESLWELLLEARRRRRRRR 84 GLFEALLELLESLWELLLEARRRRRR 85 GLFEALLELLESLWELLLEAKKKKKKKK 86 GLFEALLELLESLWELLLEAKKKKKK 87 GLFEALLELLESLWELLLEAKK 88 GLFEALLELLESLWELLLEAKKKK 89 GLFEALLELLESLWELLLEAEE 90 GLFEALLELLESLWELLLEAEEEE 91 GLFEALLELLESLWELLLEAEEEEEEGLFEALLELLESLWELLL EARR 92 GLFEALLELLESLWELLL 93 PLSSIFSRIGDPRGARRYAKMKRRRRRVARRHRRRP 94 GPFHYFQFLFPPV 95 GSSSWWQRWWPPW 96 RRRQRRKKR 97 KKKK 98 KKKKKK 99 KKKKKKKK 100 KKKKKKKKKK 101 KKKKKKKKKKKK 102 KKKKKKKKKKKKKKKK 103 KKKKKKKKKKKKKKKKKKKK 104 KKKKKKKKKKKKKKKKKKKKKKKK 105 RRRR 106 RRRRRR 107 RRRRRRRR 108 RRRRRRRRRR 109 RRRRRRRRRRRR 110 RRRRRRRRRRRRRRRR 111 RRRRRRRRRRRRRRRRRRRR 112 RRRRRRRRRRRRRRRRRRRRRRRR 113 YKA 114 KKKKKKKKWKGGGGACYGLPHLFCG 115 YKAKKKKKKKKWK 116 KTPKKAKKPKTPKKAKKP 117 KKAKKPAATRKSSKNPKKPKTVKPKKVAK 118 RGARRYSKMKRRRRRVARRHRRRP 119 TRQARRNRRRRWRERQRGSGSG 120 KRPRGRPKGSKKNWRRRKRRASRRSPRRR 121 KRGRGRPRKQPPKEPSEVPTPKRPRGRPKGSKNK 122 KEKYEKDIAAYRAKGKPAAKKGVVKAEKSKKKK 123 YKAKKKKKKKKKKWK 124 KKKKKKKGGC 125 YRARRRRRRRRWR 126 YRARRRRRRRRRRWR 127 KGDPKKPRGKMSSYAFFVQTCREEHKKKHPDASVNFSEFSKK 128 KKQLKKQLKKQLKQWK 129 KKSPKKSPKKSPKKSK 130 KLSKLEKKSKLEK 131 KLSKLEKKLSKLEKKSKLEK 132 KSLKKSLKKSLKKSK 133 KIRRRGKNKVAARTCRQRRTDR 134 KIRRRGKNKVAAQNCRKRKLET 135 KRRIRREKNKMAAAKCRNRRRELT 136 KDRSNLLERHTR 137 KRPAATKKAGQAKKKL 138 RRRRRREEEE 139 RRRRRREEEEEE 140 RRRRRREEEEEEEE 141 RRRRRRRREEEE 142 RRRRRRRREEEEEE 143 RRRRRRRREEEEEEEE 144 RRRRRRRRRRRREEEE 145 RRRRRRRRRRRREEEEEE 146 RRRRRRRRRRRREEEEEE 147 KLSKLEKK 148 SKLEK 149 KLSKLEKKLSKLEKK 150 PKKKRKVGGGRGDSP 151 LPHKSMPCG 152 GACLQHKSMPCG 153 YGLPHLFCG 154 SERSMNFCG 155 DHYSLYEDLERGTDK 156 ISLPRTSGAQRASTTR 157 EKLQTKYGLPHKVEFCG 158 TRISESQAKPGD 159 LVFFDY 160 WGGNGPTTFDCSGYTKYVFAK 161 INIGTTGWGDHYSLY 162 YDNIHG 163 AGWGKFLVGFGRV 164 SIGYPLP 165 TTHWGFTL 166 HLQIQPYPOISG 167 KLNIVSVNG 168 RGH 169 DNRIRLOAKAA 170 KIKMVISWKG 171 LPWYSYLYAVSA 172 WNLPWYYSVSPT 173 WNL 174 PWYYSVSPT 175 SSWESYKSGGGTRL 176 RDWSSQHPGRCNGETHLK 177 SLPTLTL 178 VICTGGDYSFALPVGQWPVMT 179 DKPSYQFGGHNSVDFEEDTLPKV 180 RARRRKRASATQLYQTCKASGTCPPD 181 SGDYSFALPVGQWPWMTG 182 CTGGDYSFALPVGQWPW 183 FYYDYDFFFDYWGQG 184 HLRRLRRRLLREAEG 185 DYYCAAWDDSLNGYSVF 186 YYCLQSMEDPYTFGG 187 YYCARSDGNYGYYYALDYDY 188 AARSPSYYRYDY 189 GPYYAMDYD 190 YYCQQRSSYPYTEGGAYPKAWK 191 YYCQRYDSDWSFGQGTKL 192 YYCARSGYYAMDYWGQGT 193 RVRRGACRGDCLG 194 RVRRGACRYDCLG 195 YYCAKGTHWGFWSGYFDYWGQGT 196 GRENYHGCTTHWGFTLC 197 VQATQSNQHTPRGGGSK 198 DPRAPGS 199 YYCQQRSSYPYTFGG 200 AARSPSYYRYDYGPYYAMDYD 201 GPKLTGILISILSLFVES 202 KYILRWRPKNS 203 IKVAV 204 WTPPRAQITGYRLTVGLTRR 205 AASIKVAVSADR 206 KLDAPT 207 NRWHSIYITRFG 208 PHSRN 209 SSFHFDGSGYAM 210 RGDS 211 IAFQRN 212 GRGDSP 213 TWYKIAFQRRK 214 EDGIHEL 215 SLVRNRRVITIQ 216 YRVRVTPKEKTGPMKE 217 LQVQLSR 218 SPPRRARVT 219 RKRLQVQLSIRT 220 ATETTITIS 221 NAPFPKLSWTIQ 222 VSPPRRARVTDATETTITISWRTKTETITGG 223 WTIQTTVDRGLL 224 KPDVRSYTITG 225 DTINNGRDHMILI 226 ANGQTPIQRYIK 227 MILISIGKSQKRM 228 PRARITGYIIKYEKPGSPPREVVPRPRPGV 229 PPFLMLLKGSTR 230 WQPPRARI 231 NQRLASFSNAQQS 232 WQPPRARITGYIIKYEKPG 233 ISNVFVQRMSQSPEVLD 234 YEKPGSPPREVVPRPRPGV 235 KARSFNVNQLLQD 236 KNNQKSEPLIGRKKT 237 KNSFMALYLSKG 238 EILDVPST 239 KNSFMALYLSKGRLVFALG 240 IDAPS 241 RDSFVALYLSEGHVIFAGLG 242 VVIDASTAIDAPSNL 243 KPRLQFSLDIQT 244 LDVPS 245 DGQWHSVTVSIK 246 REDV 247 FVLYLGSKNAKK 248 PHSRNRGDSP 249 LAIKNDNLVYVY 250 LWVTVRSQQRGLF 251 AYFSIVKIERVG 252 GTNNWWQSPSIQN 253 DVISLYNFKHIY 254 WVTVTLDLRQVFQ 255 FFDGSSYAVVRD 256 RQVFQVAYIIIKA 257 LHVFYDFGFGFSNG 258 LTRYKITPRRGPPT 259 LKKAQINDAKYREISIIYHN 260 LLEFTSARYIRL 261 RAYFNGQSFIAS 262 YIRLRLQRIRTL 263 SRLRGKNPTKGK 264 RRYYYSIKDISV 265 LHKKGKNSSKPK 266 SINNTAVNQRLT 267 RLKTRSSHGMIF 268 GGFLKYTVSYDI 269 GEKSQFSIRLKT 270 RDQLMTVLANVT 271 TLFLAHGRLVFM 272 ANVTHLLIRANY 273 LVFMFNVGHKKL 274 AGTFALRGDNPQG 275 TLFLAHGRLVFMFNVGHKKL 276 VLIKGGRARKHV 277 DFMTLFLAHGRLVFMGNVG 278 LSNIDYLIKAS 279 HKKLKIRSQEKY 280 LQQSRIANISME 281 GAAWKIKGPIYL 282 NLLLLLVKANLK 283 VIRDSNVVQLDV 284 HRDELLLWARKI 285 GLIYYVAHQNQM 286 KRRARDLVHRAE 287 DYATLQLQEGRLHFMFDLG 288 SQFQESVDNITK 289 KKGSYNNIVVHV 290 PGGMREKGRKAR 291 ADNLLFYLGSAK 292 MEMQANLLLDRL 293 GSAKFIDFLAIE 294 LSEIKLLISAR 295 KVSFLWWVGSGV 296 RDFTKATNIRLRFLR 297 SYWYRIEASRTG 298 ISTVMFKFRTFS 299 YFDGTGFAKAVG 300 KQANISIVDIDSN 301 NGQWHKVTAKKI 302 FSTRNESGIILL 303 AKKIKNRLELVV 304 RRQTTQAYYAIF 305 GFPGGLNQFGLTTN 306 YAIFLNKGRLEV 307 NQFGLTTNIRFRG 308 KNRLTIELEVRT 309 IRSLKLTKGTGKP 310 GLLFYMARINHA 311 AKALELRGVQPVS 312 VQLRNGFPYFSY 313 GQLFHVAYILIKF 314 HKIKIVRVKQEG 315 NVLSLYNFKTTF 316 DFGTVQLRNGFPFFSYDLG 317 SQRIYQFAKLNYT 318 NIRLRFLRTNTL 319 EVNVTLDLGQVFH 320 GKNTGDHFVLYM 321 GQVFHVAYVLIKF 322 VVSLYNFEQTFML 323 HQQDLGTAGSCLRKFSTMFLF 324 RFDQELRLVSYN 325 HQQDLGTAGSCLRKFSTMFLFCNI 326 RLVSYSGVLFFLK 327 VAEIDGIEL 328 NWRHISYITRFG 329 GIIFFL 330 KRLQVQLRSIRT 331 ASKAIQVFLLGG 332 TWYKIAFQRNRK 333 VLVRVERATVFS 334 QVFQVAYIIIKA 335 TVFSVDQDNMLE 336 GEFYFDLRLKGDK 337 RLRGPQRVFDLH 338 GTPGPQGIA 339 FDLHQNMGSVN 340 GQRDVV 341 LRAHAVDVNG 342 TAGSCLRKFSTM 343 LFSHAVSSNG 344 KGHRGF 345 TAGSCLRKFSTMFLF 346 TAGSCLRKFSTMFLFCNI 347 DLGTAGSCLRKFSTM 348 HQQDLGTAGSCLRKFSTM 349 RNIAEIIKDI 350 SIGFRGDGQTC 351 LNRQELFPFG 352 RIQNLLKITNLRIKFVK 353 KKQRFRHRNRKGYRSQ 354 SINNTAVMQRLT 355 FRHRNRKGY 356 RYRVRVTPKEKTGPMKE 357 SETTVKYIFRLHE 358 GHRGPTGRPGKRGKQGQKGDS 359 KAFDITYVRLKF 360 GDLGRPGRKGRPGPP 361 YIGSR 362 RGEFYFDLRLKGDK 363 LAGSCLARFSTM 364 LALFLSNGHFVA 365 ISRCQVCMKKRH 366 PGRWHKVSVRWE 367 TDIPPCPHGWISLWK 368 VRWGMQQIQLVV 369 TAIPSCPEGTVPLYS 370 KMPYVSLELEMR 371 GPAGKDGEAGAQG 372 VLLQANDGAGEF 373 GLPGER 374 DGRWHRVAVIMG 375 LAGSCLPVFSTL 376 APVNVTASVQIQ 377 TAGSCLRRFSTM 378 KQGKALTQRHAK 379 TAGSCLRKF 380 RYVVLPR 381 TAGSCL 382 SPYTFIDSLVLMPY 383 TAG 384 PDSGR 385 QQNLGSVNVSTG 386 SRATAQKVSRRS 387 DPGYIGSR 388 GSLSSHLEFVGI 389 VILQQSAADIAR 390 RNRLHLSMLVRP 391 KDISEKVAVYST 392 APMSGRSPSLVLK 393 LGTIPG 394 AFGVLALWGTRV 395 TDIRVTLNRLNTF 396 IENVVTTFAPNR 397 AFSTLEGRPSAY 398 LEAEFHFTHLIM 399 TSAEAYNLLLRT 400 HLIMTFKTFRPA 401 LNRRYEQARNIS 402 KTWGVYRYFAYD 403 SLLSQLNNLLDQ 404 TNLRIKFVKLHT 405 RDIAEIIKDI 406 KRLVTGQR 407 SHAVSS 408 GPGVVVVERQYI 409 ADTPPV 410 NEPKVLKSYYYAI 411 LRAHAVDING 412 YYAISDFAVGGR 413 DSITKYFQMSLE 414 LPFFNDRPWRRAT 415 YTALIIATDN 416 FDPELYRSTGHGGH 417 VITVKDINDN 418 TNAVGYSVYDIS 419 GLDRESYPYY 420 APVKFLGNQVLSY 421 MKVSATDADD 422 SFSFRVDRRDTR 423 PQVTRGDVFTMP 424 TWSKVGGHLRPGIVQSG 425 KEAEREVTDLLR 426 RGDV 427 AAEPLKNIGILF 428 FALWDAIIGEL 429 VGVAPG 430 LWPLLAVLAAVA 431 PGVGV 432 VFDNFVLK 433 TSIKIRGTYSER 434 TTSWSQCSKS 435 DPETGV 436 KRSR 437 QGADTPPVGV 438 SVVYGLR 439 PLDREAIAKY 440 DGRGDSVAYG 441 HAVDI 442 LALERKDHSG 443 DQNDN 444 YSMKKTTMKIIPFNRLTIG 445 QDPELPDKNM 446 RGDF 447 LVVQAADLQG 448 GVYYQGGTYSKAS 449 NDDGGQFVVT 450 TAGSCLRKFSCL 451 YILHVAVTN 452 CNYYSNSYSFWLASLNPER 453 TYRIWRDTAN 454 TGLSCLQRFTTM 455 GFTCECSIGFRGDGQTCYGIVFWSEV 456 HHLGGAKQAGDV 457 SCLPGFSGDGRACRDVDECGH 458 MAPRPSLAKKQRFRHRNRKGYRSQRGHSRG 459 KKQKFRHRNRKGYRSQ 460 KKQKFKHRNRKGYRS 461 KKQKFRRRNRKGYRSH 462 TAIPPCPHGWISLWK 463 KKQKSRHRSRKRYRS 464 KKQKSRRRSRKGYRS 465 ISRCTVC 466 ISRCQVCMKRRH 467 VSRCTVC 468 TDIPPCPQGWISLWK 469 TVKAGELEKIISRCQVMKKRH 470 TDIPSCPHGWISLWK 471 TDIPPCPAGWISLWK 472 TEIPPCPQGWISLWK 473 TDVPPCPQGWISLWK 474 RLVSYNGILFFLK 475 RLVSYSGVIFFLK 476 RLVSYNGILFFL 477 RLVSYSGIIFFLK 478 RFEQELRLVSYSGVLFFLKQ 479 RLVSYNGIIFFLK 480 DPAFKIEDPYSPRIQNLLKITNLRIKFVKL 481 TKRFEQELRLVSYSGVLFFL 482 GGRLKYSVAF 483 GGFLRYTVSYDI 484 GGFLKYTVSYDV 485 LGNKLTAFGGFLKYTVSYDIPV 486 GGYLKYTVSYDI 487 GEIFFDMRLKGDK 488 GEIYFDLRLKGDK 489 GEIYLDMRLKGDK 490 IGQPGAKGEPGEFYFDLRLKGDKGDPGFPG 491 GEVFFDMRLKGDK 492 LAGSCLPIFSTL 493 AHNQDLGLAGSCLARFSTMPFLYCNPGDIC 494 QEKAHNQDLGLAGSCLPVFSTLPFAYCNIH 495 LAGSCLPVFSTM 496 GNKRAHGQDLGTAGSCLRRFSTMPFMFCNI 497 RAHGQDLGTAGSCLRRFSTMP 498 RKRLQVQLNIRT 499 HLVLPLQQSDVRKRLQVQLSIRTFASSGLI 500 RKRLSVQLRIRT 501 DLGTAGSCLRRFSTM 502 RNIAEIIKDI 503 TAGSCLRKFSTMRRRRRRRRRRRR 504 FTLTGLLGTLVTMGLLT 505 APYKAWK

TABLE 2 Relative Fluorescence of Transfection of HeLa Cells SEQ ID NO RF* SEQ ID NO RF SEQ ID NO RF DOTMA 7551 327 5345 357 22679 107 75 328 32528 358 15132 205 26368 332 9198 359 3136 216 6181 335 26954 360 8516 218 11179 336 25262 361 3698 219 13721 338 6241 363 2590 220 9398 341 4108 365 36093 224 5559 342 33666 367 39008 226 7340 343 5910 369 14444 229 8816 344 14415 371 5180 230 8944 345 8493 373 8992 234 3867 347 22527 375 41076 236 7202 348 22289 377 15091 236 5042 349 4433 379 27424 237 21288 350 13313 381 22652 238 6067 351 12279 383 8012 239 2717 352 32126 450 21045 256 2243 353 29119 452 13888 268 25885 354 4403 454 34550 323 14067 355 32628 503 25368 326 18946 *RF = Relative Fluorescence

TABLE 3 Relative Fluorescence of Transfection of HuVec Cells SEQ ID NO RF* SEQ ID NO RF SEQ ID NO RF DOTMA 12230 328 3614 359 3024 205 8309 332 4221 360 24042 216 14693 335 6350 361 6017 218 14827 336 5366 363 1383 219 6237 338 12000 365 14764 220 8737 341 15906 367 13354 224 15945 342 12804 369 6536 226 20864 343 16239 371 10669 229 5452 344 11867 373 28811 230 9067 345 2939 375 5542 234 13956 347 20728 377 9326 235 26940 348 21214 379 14573 236 14418 349 22907 381 17542 237 2302 350 13163 383 20267 238 11083 351 15379 450 20911 239 1404 352 3130 452 1841 256 3030 353 8772 454 13336 268 5403 354 19284 503 12123 323 12815 355 14810 326 4932 357 6009 327 21018 358 25398 *RF = Relative Fluorescence

TABLE 4 Relative Fluorescence of Transfection of NL-1 iPS Cells SEQ ID NO RF* SEQ ID NO RF SEQ ID NO RF DOTMA 8965 327 31383 357 15624 107 1441 328 8611 358 21956 205 13140 332 8725 359 5548 216 19626 335 14424 360 27572 218 17049 336 14875 361 9363 219 5770 338 17288 363 4189 220 15892 341 20446 365 6364 224 25209 342 11493 367 17545 226 24920 343 21726 369 13124 229 13491 344 10895 371 17587 230 14524 345 7836 373 36290 234 14410 347 21865 375 5196 236 43542 348 21645 377 5474 236 22256 349 33103 379 6894 237 8632 350 19132 381 9644 238 15856 351 24646 383 21983 239 4129 352 11628 450 29856 256 1825 353 9248 452 10349 268 15697 354 24043 454 18100 323 21694 355 7910 503 19014 326 9239 *RF = Relative Fluorescence

TABLE 5 Relative Fluorescence of Transfection of C2C12 Cells SEQ ID NO RF* SEQ ID NO RF SEQ ID NO RF DOTMA 1289 328 5507 359 5693 205 2102 332 537 360 2090 216 1001 335 4689 361 585 218 3706 336 9647 363 1080 219 1346 338 2290 365 5390 220 1470 341 2141 367 16207 224 1469 342 9496 369 3322 226 1664 343 3218 371 983 229 1164 344 1678 373 3037 230 2606 345 6569 375 5633 234 681 347 4457 377 1710 236 958 348 8625 379 3189 236 2142 350 2631 381 8834 237 6491 351 3530 383 1876 238 1550 352 3324 450 3795 239 10620 353 4291 452 21798 256 3207 354 1912 454 9280 268 2568 355 1900 501 5913 323 7698 357 4506 502 2589 326 8553 358 2271 503 3973 327 2043 *RF = Relative Fluorescence

TABLE 6 Relative Fluorescence of Transfection of Human Fibroblast Cells SEQ ID NO RF* SEQ ID NO RF SEQ ID NO RF DOTMA 3397 328 5641 358 5665 205 8550 332 5178 359 3206 216 3117 335 8534 360 5347 218 11230 336 10449 361 7014 219 7389 338 5625 363 3008 220 4516 341 2284 365 5219 224 5995 342 9525 367 10036 226 3431 343 4590 369 7590 229 6811 344 12704 371 4584 230 11771 345 2816 373 4872 234 4145 347 9255 375 7305 236 3630 348 11802 377 6638 236 3000 349 8810 379 8520 237 2184 350 7105 381 9953 238 3348 351 8061 383 5896 239 4084 352 3059 450 6996 256 2656 353 8653 452 2779 268 4568 354 4998 454 7568 323 4826 355 6821 501 9473 326 3070 357 7167 503 13085 327 4662 *RF = Relative Fluorescence

TABLE 7 Relative Fluorescence of Transfection of Jurkat Cells SEQ ID NO RF* SEQ ID NO RF SEQ ID NO RF DOTMA 9084 328 4770 358 18820 205 2298 332 3052 359 1880 216 3570 335 4567 360 16607 218 21451 336 4813 361 7006 219 10762 338 4475 363 2432 220 6428 341 18042 365 5298 224 13170 342 12825 367 4365 226 12976 343 23499 369 11085 229 8079 344 10160 371 6093 230 10229 345 2462 373 12628 234 5441 347 17720 375 4272 236 11006 348 15585 377 6785 236 4593 349 23167 379 7711 237 1501 350 9184 381 10806 238 6278 351 9730 383 14910 239 2343 352 3150 450 8779 256 3322 353 11107 452 2554 268 3236 354 16705 454 8224 323 2900 355 8132 501 12350 326 3018 357 2256 503 9411 327 14546 *RF = Relative Fluorescence

TABLE 8 Visual Confirmation of Transfection of Cells Cell Line SEQ ID NOs Rat Cortical Neurons 220, 236, 238, 323, 327, 336, 338, 341, 343, 347, 348, 350, 351, 352, 354, 367, 369, 373, 375, 377, 454 THP-1 219, 229, 230, 239, 323, 328, 332, 341, 343, 350, 351, 357, 358, 375, 450, 454 Human Skeletal Muscle 218, 219, 230, 328, 336, 344, 350, 351, 353, 355, 365, 375

TABLE 9 Relative Fluorescence DOTMA/SEQ ID NO: 72/Peptide as Compared with Lipofectamine 2000 for the Transfection of HeLa Cells Transfection RF* Agent 0.1^(†) 0.2^(†) 0.3^(†) 0.4^(†) Lipo^(#) 12694 22154 21542 19286 DOTMA/72^(§) 10178 11133 8021 7032 SEQ ID NO^(‡) 218 12686 13103 10151 10081 219 12135 13841 13531 11712 236 5993 8846 8492 7316 237 8986 9753 8015 8288 268 10162 9934 10792 9519 323 15537 16620 10839 9244 326 6887 9487 10330 9227 328 11037 12229 10801 10951 335 12866 12458 11547 9753 336 14442 16702 13434 11334 341 6406 7469 8020 7546 342 41299 36040 28841 18351 343 6961 8626 8577 8160 344 13315 16387 12564 12511 347 23188 21493 16814 14140 348 17413 18615 16164 15054 350 24092 23238 19802 22255 351 7678 11499 10575 8791 353 36315 44772 36882 25802 355 18362 27990 22367 18289 357 7718 11798 9229 9107 358 12331 12683 13686 11097 360 9946 11168 10381 8995 365 26620 43775 36054 21540 367 10427 21411 23001 17529 369 8737 16706 14880 12645 375 22457 30891 34887 29024 377 39115 40072 32914 22457 379 50018 47049 39036 26448 381 34187 37463 27007 20088 450 11962 17346 12553 10241 452 6276 12671 12047 10918 454 34033 37099 27412 16023 501 23571 23993 20410 14749 503 12827 20006 17101 16206 *RF = Relative Fluorescence ^(†)Volume of DOTMA/SEQ ID NO: 72/Peptide in μL in well of a 96 well plate ^(#)Lipofectamine 2000 ^(§)DOTMA and SEQ ID NO: 72 with no additional peptide ^(‡)Peptide mixed with DOTMA/SEQ ID NO: 72 

1. A transfection complex comprising a transfection enhancer and a cell surface ligand.
 2. The transfection complex of claim 1, wherein the transfection enhancer is: i) a peptide; ii) an amphipathic peptide; iii) a fusion peptide; iv) selected from the group consisting of SEQ ID NOs:1-505; v) selected from the group consisting of SEQ ID NOs:107, 205, 216, 218, 219, 220, 224, 226, 229, 230, 234, 236, 236, 237, 238, 239, 256, 268, 323, 326, 327, 328, 332, 335, 336, 338, 341, 342, 343, 344, 345, 347, 348, 349, 350, 351, 352, 353, 354, 355, 357, 358, 359, 360, 361, 363, 365, 367, 369, 371, 373, 375, 377, 379, 381, 383, 450, 452, 454, and 503; vi) selected from the group consisting of SEQ ID NOs:205, 237, 268, 326, 328, 335, 336, 342, 347, 348, 352, 353, 355, 357, 358, 365, 367, 377, 379, 381, 450, 454, and 503; vii) selected from the group consisting of SEQ ID NOs:205, 216, 218, 219, 220, 224, 226, 229, 230, 234, 236, 236, 237, 238, 239, 256, 268, 323, 326, 327, 328, 332, 336, 338, 341, 342, 343, 344, 345, 347, 348, 349, 350, 351, 352, 353, 354, 355, 357, 358, 359, 360, 361, 363, 365, 367, 369, 371, 373, 375, 377, 379, 381, 383, 450, 452, 454, and 503; viii) selected from the group consisting of SEQ ID NOs:236, 358, and 373; ix) selected from the group consisting of SEQ ID NOs:107, 205, 216, 218, 219, 220, 224, 226, 229, 230, 234, 236, 236, 237, 238, 239, 256, 268, 323, 326, 327, 328, 332, 335, 336, 338, 341, 342, 343, 344, 345, 347, 348, 349, 350, 351, 352, 353, 354, 355, 357, 358, 359, 360, 361, 363, 365, 367, 369, 371, 373, 375, 377, 379, 381, 383, 450, 452, 454, and 503; x) selected from the group consisting of SEQ ID NOs:216, 224, 226, 236, 236, 323, 327, 341, 343, 347, 348, 349, 350, 351, 354, 358, 360, 373, 383, 450, 454, and 503; xi) selected from the group consisting of SEQ ID NOs:205, 216, 218, 219, 220, 224, 226, 229, 230, 234, 236, 236, 237, 238, 239, 256, 268, 323, 326, 327, 328, 332, 335, 336, 338, 341, 342, 343, 344, 345, 347, 348, 350, 351, 352, 353, 354, 355, 357, 358, 359, 360, 361, 363, 365, 367, 369, 371, 373, 375, 377, 379, 381, 383, 450, 452, 454, 501, 502, and 503; xii) selected from the group consisting of SEQ ID NOs:218, 230, 237, 239, 256, 323, 326, 328, 335, 336, 342, 343, 345, 347, 348, 352, 357, 359, 367, 375, 379, 381, 450, 452, 454, 501, 502, and 503; xiii) selected from the group consisting of SEQ ID NOs:205, 216, 218, 219, 220, 224, 226, 229, 230, 234, 236, 236, 237, 238, 239, 256, 268, 323, 326, 327, 328, 332, 335, 336, 338, 341, 342, 343, 344, 345, 347, 348, 349, 350, 351, 352, 353, 354, 355, 357, 358, 359, 360, 361, 363, 365, 367, 369, 371, 373, 375, 377, 379, 381, 383, 450, 452, 454, 501, and 503; xiv) selected from the group consisting of SEQ ID NOs:205, 218, 219, 229, 230, 335, 336, 342, 344, 348, 349, 350, 351, 353, 355, 357, 361, 367, 369, 375, 379, 381, 450, 454, 501, and 503; xv) selected from the group consisting of SEQ ID NOs:205, 216, 218, 219, 220, 224, 226, 229, 230, 234, 236, 236, 237, 238, 239, 256, 268, 323, 326, 327, 328, 332, 335, 336, 338, 341, 342, 343, 344, 345, 347, 348, 349, 350, 351, 352, 353, 354, 355, 357, 358, 359, 360, 361, 363, 365, 367, 369, 371, 373, 375, 377, 379, 381, 383, 450, 452, 454, 501, and 503; xvi) selected from the group consisting of SEQ ID NOs:218, 349, and 358; xvii) selected from the group consisting of SEQ ID NOs: 220, 236, 238, 323, 327, 336, 338, 341, 343, 347, 348, 350, 351, 352, 354, 367, 369, 373, 375, 377, and 454; xviii) selected from the group consisting of SEQ ID NOs:219, 229, 230, 239, 323, 328, 332, 341, 343, 350, 351, 357, 358, 375, 450, and 454; xix) selected from the group consisting of SEQ ID NOs: 218, 219, 230, 328, 336, 344, 350, 351, 353, 355, 365, and 375; or xx) selected from the group consisting of SEQ ID NOs:205, 216, 218, 219, 220, 226, 229, 230, 236, 237, 238, 239, 256, 268, 323, 326, 327, 328, 332, 336, 338, 341, 342, 343, 344, 345, 347, 348, 349, 350, 351, 352, 353, 354, 355, 357, 358, 359, 360, 361, 365, 367, 369, 373, 375, 377, 379, 381, 393, 450, 452, 454, 501, and
 503. 3-21. (canceled)
 22. The transfection complex of claim 1, further comprising at least one helper lipid component, wherein the helper lipid component is optionally: i) selected from the group consisting of a pegylated lipid, a cationic lipid, a pegylated cationic lipid, a neutral lipid, a pegylated neutral lipid, a cationic polymer, a pegylated cationic polymer, a targeting moiety, and a combination thereof-; ii) selected from the group consisting of cholesterols, cholesterol derivatives, sterols, phytosterols, zoosterols, and hopanoids-; iii) selected from the group consisting of N-(2-bromoethyl)-N,N-dimethyl-2,3-bis(9-octadecenyloxy)-propanaminimun bromide (BMOP), dipalmitoylphosphatidylethanolamine 5-carboxyspermylamide (DDPES), DSPC, dioleoylphosphatidylethanolamine (DOPE), formulation of cetyltrimethylammonium bromide (CATB) and DOPE (CTAB:DOPE), 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), DMG, 4-dimethylaminopyridine (DMAP), dimyristoylphospatidylethanolamine (DMPE), DOMG, DMA, Dioleoylphosphatidylcholine (DOPC), dimyristoylphosphatidylcholine (DMPC), Dipalmitoylethylphosphatidylcholine (DPEPC), dioleoydimethylammonium chloride (DODAC), 1,3-di-oleoyloxy-2-(6-carboxyspermyl)-propylamid (DOSPER), N-[1-(2,3-dioleyloxy)propyl]-N,N,N-trimethylammoniumchloride (DOTMA), didoceyl methylammonium bromide (DDAB), N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethyl-ammonium methylsulfate (DOTAP), DOTAP.Cl, 3,β-N,(N′,N′-dimethylaminoethane)-carbamoyl]cholesterol (DC-chol), 2-(sperminecarboxamido)ethyl)-N,N-dimethyl-lammonium trifluoroacetate (DOSPA), O,O′-ditetradecanoyl-N-(alphatrimethylammonioacetyl) diethanolamine chloride (DC-6-14), dicaproylphosphtidylethanolamine (DCPE), dilauryl oxypropyl-3-dimethylhydroxy ethylammonium bromide (DLRIE), 1,2-dioleoyl-3-dimethylammonium-propane (DODAP), Ethyl-PC, 2,3-dioleoyloxy-N-[2-(sperminecarboxamidoethyl]-N,N-di-met-hyl-1-propanaminium trifluoroacetate (DOSPA), dioctadecylamidoglycyl carboxyspermine (DOGS), N-[1-(2,3 dimyristyloxy)propyl]-N,N-dimethyl-N-(2-hydroxyethyl) ammonium bromide (DMRIE), Dioleoylethyl-phosphocholine (DOEPC), N-[1-(2,3-dioleoyloxy)propyl]-N-[1-(2-hydroxyethyl)]-N,Ndimethylammonium iodide (DOHME), N-(3-aminopropyl)-N,N-dimethyl-2,3-bis(dodecyloxy)-1-propaniminium bromide/dioleylphosphatidylethanolamine (GAP-DLRIE:DOPE), dipalmitoylphosphatidylcholine (DPPC), 1,2-dioleoyl-sn-glycero-3-[phospho-rac-(3-lysyl(1-glycerol)).Cl (DOPG), N-lauroylsarcosine, (R)-(+)-limonene, lecithins (and derivatives thereof); phosphotidylethanolamine (and derivatives thereof); phosphatidylethanolamines, dioleoylphosphatidylethanolamine), diphytanoylphosphatidylethanolamine (DPhPE), dipalmitoylphosphatidylethanolamine (DPPE), dipalmiteoylphosphatidylethanolamine, 3-β-[1-ornithinamidecarbamoyl]-cholesterol (O-Chol), palmitoyloleoylphosphatidylethanolamine (POPE); distearoylphosphatidylethanolamine; phosphotidylcholine; phosphatidylcholines; dipalmitoylphosphatidylcholine (DPPC) palmitoyloleoylphosphatidylcholine (POPC); distearoylphosphatidylcholine; phosphatidylglycerol; piperazine-based cationic lipids; a phosphatidylglycerol; dioleoylphosphatidylglycerol (DOPG); dipalmitoylphosphatidyl-glycerol (DPPG); distearoylphosphatidylglycerol; phosphatidylserine (and derivatives thereof); phosphatidylserines; dioleoyl- or dipalmitoylphosphatidylserine; a diquaternary ammonium salt; 1,4-bis[(3-(3-amino-2-hydroxypropyl)-palmitylamino)propyl]piperazine; N-(3-aminopropyl)-N,N′-bis-(dodecyloxyethyl)-piperazinium bromide; N-(3-amino-propyl)-N,N′-bis-(oleyloxyethyl)-piperazinium bromide; N-(3-aminopropyl)-N,N′-bis-(palmityloxyethyl)-piperazinium bromide; N-(3-aminopropyl)-N,N′-bis-(myristyl-oxyethyl)-piperazinium bromide; N-(3-aminopropyl)-N′-methyl-N,N′-(bis-2-dodecyloxy-ethyl)-piperazinium bromide; N-(3-aminopropyl)-N′-methyl-N,N′-(bis-2-oleyloxyethyl)-piperazinium bromide; N-(3-aminopropyl)-N′-methyl-N,N′-(bis-2-palmityloxyethyl)-piperazinium bromide; N-(3-aminopropyl)-N′-methyl-N,N′-(bis-2-myristyloxyethyl)-piperazinium bromide; 1,4-bis[(3-(3-aminopropyl)-oleylamino)-2-hydroxy-propyl]-piperazine; 1,4-bis[(3-(3-aminopropyl)-myristylamino)-2-hydroxy-propyl]piperazine; or 1,4-bis[(3-(3-aminopropyl)-palmitylamino)-2-hydroxy-propyl]piperazine; 3-alkyloxy-2-hydroxy-1-histidylamidopropane, 3-alkyloxy-2-hydroxy-1-aminopropane; 4-alkyloxy-3-hydroxy-1-histidylamidopropane, 4-alkyloxy-3-hydroxy-1-aminopropane; 5-alkyloxy-4-hydroxy-1-histidylamidopropane, 5-alkyloxy-4-hydroxy-1-aminopropane; 6-alkyloxy-5-hydroxy-1-histidylamidopropane; 6-alkyloxy-4-hydroxy-1-aminopropane; 2,3-dialkoxy-1,4-bis(N-methyl-N-carboxyspermineamido)aminobutane; 2,3-dialkoxy-1,4-bis(N-methyl-N-histidinylamido)aminobutane; 2,3-dialkoxy-1,4-bis(N-methyl-N-arginyl-amido)aminobutane; 2,3-dialkoxy-1,4-bis(N-methyl-N-lysinylamido)aminobutane; 2,3-dialkoxy-1,4-bis(N-methyl-N′-ornithinylamido)aminobutane; 2,3-dialkoxy-1,4-bis(N-methyl-N-serinylamido)aminobutane; 2,3-dialkoxy-1,4-bis(N-methyl-N-homoerinyl-amido)aminobutane; 2,3-dialkoxy-1,4-bis(N-methyl-N-(diaminobutanyl)amido)aminobutane; 2,3-dialkoxy-1,4-bis(N-methyl-N-(diaminopropyl)amido)aminobutane; 2,3-dialkoxy-1,4-bis(N-methyl-N-(2-hydroxylpropylamine))aminobutane; 2,3-dialkoxy-1,4-bis(N-methyl-N-(2-diaminopropyl))aminobutane; 2,3-dialkoxy-1,4- and bis(N-methyl-N-propylamine)aminobutane N;N′-dioleyl-N,N,N′,N′-tetramethyl-1,2-ethanediamine (TmedEce); N,N′-dioleyl-N,N,N′,N′-tetramethyl-1,3-propanediamine (PropEce); N,N′-dioleyl-N,N,N′,N′-tetramethyl-1,6-hexanediamine (HexEce); and their corresponding N,N′-dicetyl saturated analogues (TmedEce, PropEce and HexEce); a diphosphatidylglycerol; a fatty acid ester; a monocationic transfection lipid; 1-deoxy-1-[dihexadecyl(methyl)ammonio]-D-xylitol; 1-deoxy-1-[methyl(ditetradecyl)ammonio]-Darabinitol; 1-deoxy-1-[dihexadecyl(methyl)ammonio]-D-arabinitol; a 1-deoxy-1-[methyl(dioctadecyl)-ammonio]-darabinitol; glycerol ester; sphingolipids; cardolipin; a cerebroside; a ceramide; and combinations thereof-; iv) selected from the group consisting of cholesterol and derivatives thereof, a 3βOH-sterol and derivatives thereof, phosphatidyl choline, LIPOFECTIN® CELLFECTIN® (1:1.5 (M/M) formulation of N,N′,N″,N′″-tetramethyl-N,N,N′,N″,N′″-tetrapalmitylspermine (TMTPS), dioleoyl phosphatidylethanolamine (DOPE), LIPOFECTACE®, GS 2888 CYTOFECTIN®, FUGENE 6®, EFFECTENE®, and LIPOFECTAMINE®, LIPOFECTAMINE 2000®, LIPOFECTAMINE PLUS®, LIPOTAXI®, POLYECT®, SUPERFECT®, TFXNT™, TRANSFAST™, TRANSFECTAM®, TRANSMESSENGER®, vectamidine (3-tetradecylamino-N-tert-butyl-N′-tetradecylpropionamidine (a.k.a. diC14-amidine), OLIGOFECTAMINE MessengerMAX, GeneIn™, TransfeX™, LipofectAmine 3000, Lipofectin®, DMRIE-C, CellFectin®, LipofectAce®, Fugene®, Fugene® HD, Tfx-10®, Tfx-20®, Tfx-50®, DNA-In, Transfectin™, SilentFect™, Effectene®, ViaFect™, DC-chol, GenePorter®, DharmaFect 1®, DharmaFect 2®, DharmaFect 3®, DharmaFect 4®, Escort™ III, Escort™ IV, and DOGS; v) the cationic lipid of Formula I:

or a pharmaceutically acceptable salt thereof, where W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(NH₂)—CH₂—(CH₂)_(n)—NH₂, n=0-6, y=0; or W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(NH₂)—CH₂—(CH₂)_(n)—OH, n=0-6, y=0; or W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(OH)—CH₂—(CH₂)_(n)—NH₂, n=0-6, y=0; or W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(NH-iso-butyl)-CH₂—(CH₂)_(n)—O-iso-butyl, n=0-6, y=0; or W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(NH₂)—CH₂—(CH₂)_(n)—C(═NH)—NH₂, n=0-6, y=0; or W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(NH₂)—CH₂—(CH₂)_(n)-His, n=0-6, y=0; or W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)-spermine, y=0; or W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═H, y=0; or W¹═W²═CH₂—N(R³R⁴), R²=C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═CH₂(CH₂)_(m)—NH₂; m=1-6, y=0; or W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═CH₂(CH₂)_(m)—NH—C(═O)-spermine; m=1-6, y=0; or W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═CH₂(CH₂)_(m)—NH—(C═O)-amino acid side chain; m=1-6, y=0; or W¹═W²═CH₂—N(R³R⁴), R²=C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═(CH₂)_(m)(CH—OH)(CH₂)_(m)—NH₂, y=0; or W¹═W²═CH₂—N(R³R⁴), R²=C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═CH₂(CH₂)_(n)—NH₂, y=0; or W¹═H W²═CH₂—N(R³R⁴)CH₂—R⁵; R³═R⁴═CH₃; R⁵═H, y=0; or W¹═H; W²═CH₂—O—P(═O)(OMe)-O—CH₂CH₂—NH—C(═O)-spermine, y=0; or W¹═H; W²═CH₂—O—P(═O)(OMe)-O—CH₂CH₂—NH—C(═O)-amino acid side chain, y=0; or W¹═H; W²═CH₂—O—P(═O)(OMe)-O—CH₂CH₂—N*(CH₃)₃Cl, y=0; or W¹═H; W²═CH₂—O—P(═O)(O⁻)—O—CH₂CH₂—NH—C(═O)-spermine, y=0; or Z═(CH₂)_(q), W¹ ═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(NH₂)—CH₂—(CH₂)_(n)—NH₂, n=0-6, q=1-3, y=1; or Z═(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(NH₂)—CH₂—(CH₂)_(n)—OH, n=0-6, q=1-3, y=1; or Z═(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(OH)—CH₂—(CH₂)_(n)—NH₂, n=0-6, q=1-3, y=1; or Z═(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(NH-iso-butyl)-CH₂—(CH₂)_(n)—O-iso-butyl, n=0-6, y=1; or Z═(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(NH₂)—CH₂—(CH₂)_(n)—C(═NH)—NH₂, n=0-6, q=1-3, y=1; or Z═(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(NH₂)—CH₂—(CH₂)_(n)-His, n=0-6, q=1-3, y=1; or Z═(CH₂)_(q)W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)-spermine, q=1-3, y=1; or Z═(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═H, q=1-3, Y=1; or Z═(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═CH₂(CH₂)_(m)—NH₂; m=1-6, q=1-3, Y=1; or Z═(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═CH₂(CH₂)_(m)—NH—C(═O)-spermine; m=1-6, q=1-3, Y=1; or Z═(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═CH₂(CH₂)_(m)—NH—(C═O)-amino acid side chain; m=1-6, q=1-3, Y=1; or Z═(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═(CH₂)_(m)(CH—OH)(CH₂)_(m)—NH₂, q=1-3, y=1; or Z═(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═CH₂(CH₂)_(m)—NH₂, q=1-3, y=1; or Z═(CH₂)_(q)—N(R³)—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(NH₂)—CH₂—(CH₂)_(n)—NH₂, n=0-6, q=1-3, y=1; or Z═(CH₂)_(p))—N(R³)—(CH₂)_(p), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(NH₂)—CH₂—(CH₂)_(n)—OH, n=0-6, q=1-3, Y=1; or Z═(CH₂)_(q)—N(R³)—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(OH)—CH₂—(CH₂)_(n)—NH₂, n=0-6, q=1-3, y=1; or Z═(CH₂)_(q)—N(R³)—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(NH-iso-butyl)-CH₂—(CH₂)_(n)—O-iso-butyl, n=0-6, y=1; or Z═(CH₂)_(q)—N(R³)—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(NH₂)—CH₂—(CH₂)_(n)—C(═NH)—NH₂, n=0-6, q=1-3, y=1; or Z═(CH₂)_(q)—N(R³)—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(NH₂)—CH₂—(CH₂)_(n)-His, n=0-6, q=1-3, Y=1; or Z═(CH₂)_(q)—N(R³)—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)-spermine, q=1-3, Y=1; or Z═(CH₂)_(q)—N(R³)—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═H, q=1-3, Y=1; or Z═(CH₂)_(q)—N(R³)—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═CH₂(CH₂)_(m)—NH₂; m=1-6, q=1-3, y=1; or Z═(CH₂)_(q)—N(R³)—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═CH₂(CH₂)_(m)—NH—C(═O)-spermine; m=1-6, q=1-3, Y=1; or Z═(CH₂)_(q)—N(R³)—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═CH₂(CH₂)_(m)—NH—(C═O)-amino acid side chain; m=1-6, q=1-3, Y=1; or Z═(CH₂)_(q)—N(R³)—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═(CH₂)_(m)(CH—OH)(CH₂)_(m)—NH₂, q=1-3, y=1; or Z═(CH₂)_(q)—N(R³)—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═CH₂(CH₂)_(n)—NH₂, q=1-3, y=1; Z═(CH₂)_(q)—S—S—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(NH₂)—CH₂—(CH₂)_(n)—NH₂, n=0-6, q=1-3, Y=1; or Z═(CH₂)_(q)—S—S—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(NH₂)—CH₂—(CH₂)_(n)—OH, n=0-6, q=1-3, y=1; or Z═(CH₂)_(q)—S—S—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(OH)—CH₂—(CH₂)_(n)—NH₂, n=0-6, q=1-3, y=1; or Z═(CH₂)_(q)—S—S—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(NH-iso-butyl)-CH₂—(CH₂)_(n)—O-iso-butyl, n=0-6, v=1; or Z═(CH₂)_(q)—S—S—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(NH₂)—CH₂—(CH₂)_(n)—C(═NH)—NH₂, n=0-6, q=1-3, y=1; or Z═(CH₂)_(q)—S—S—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)—C(NH₂)—CH₂—(CH₂)_(n)-His, n=0-6, q=1-3, y=1; or Z═(CH₂)_(q)—S—S—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃, R⁴═—C(═O)-spermine, q=1-3, Y=1; or Z═(CH₂)_(q)—S—S—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═H, q=1-3, y=1; or Z═(CH₂)_(q)—S—S—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═CH₂(CH₂)_(m)—NH₂; m=1-6, q=1-3, y=1; or Z═(CH₂)_(q)—S—S—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═CH₂(CH₂)_(m)—NH—C(═O)-spermine; m=1-6, q=1-3, y=1; or Z═(CH₂)_(q)—S—S—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═CH₂(CH₂)_(m)—NH—(C═O)-amino acid side chain; m=1-6, q=1-3, y=1; or Z═(CH₂)_(q)—S—S—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═(CH₂)_(m)(CH—OH)(CH₂)_(m)—NH₂, q=1-3, y=1; or Z═(CH₂)_(q)—S—S—(CH₂)_(q), W¹═W²═CH₂—N(R³R⁴), R²═C₈-C₂₂ alkyl, X═O; R³═CH₃; R⁴═CH₂(CH₂)_(n)—NH₂, q=1-3, y=1. 23-27. (canceled)
 28. The transfection complex of of claim 1, wherein the cell surface ligand comprises a nucleic acid binding moiety, wherein the nucleic acid binding moiety: i) is a DNA binding domain; ii) comprises a group selected from the group consisting of a polycationic peptide sequence, a polyamine, a peptide nucleic acid, spermine, spermidine, carboxyspermidine, carboxy spermine, spermine and spermidine analogs, and nucleic acid intercalaters; or iii) comprises a peptide; iv) binds to nucleic acid molecule selected from the group consisting of primers, probes, oligonucleotides, vectors, constructs, plasmids, genes, transgenes, genomic DNA, cDNA, RNA, mRNA, tRNA, miRNA, RNAi, siRNA, shRNA, stRNA, guide-RNA, PCR products, restriction fragments, mRNA reprograming molecules, telomerase mRNA molecules, Cas9 mRNA or DNA molecules that code for 2RNA, CRE mRNA molecules, LoxP containing DNA molecules, and SV40T antigen mRNA and DNA molecules; v) comprises a sequence selected from the group consisting of SEQ ID NOs:93 and 97-137; vi) is a nucleic acid condensing peptide, optionally comprising a sequence selected from the group consisting of SEQ ID NOs:33, 93, 97-127, 129, 132-137, and 147-149; or vii) is functionally linked, by a linkage comprising a covalent link or a spacer, to an amino acid sequence of the cell surface ligand peptide derived from the adhesion protein or a livid; viii) comprises spermine, spermine derivative, spermidine, histones or fragments thereof, protamines or fragments thereof, HMG proteins or fragments thereof, poly-lysine, poly-arginine, poly-histidine, polyamines, cationic peptides, nucleic acid interculaters, protein nucleic acid sequences, and aptamers. 29-31. (canceled)
 32. The transfection complex of claim 2, wherein the peptide comprises an amino acid sequence derived from a cell binding adhesion protein, wherein the adhesion protein is optionally selected from the group consisting of collagen, fibronectin, lamin, veronectin, cadherin, nidogen, fibrinogen, elastin, bone asialoprotein, osteopontin and tenascin-C, or wherein the peptide comprises at least 5 amino acid residues of the cell binding adhesion protein. 33-34. (canceled)
 35. The transfection complex of claim 1, wherein the cell surface ligand facilitates the delivery of a nucleic acid molecule into a cell or a tissue.
 36. The transfection complex of claim 1, wherein the delivery into the cell or the tissue is either in vivo or in vitro. 37-41. (canceled)
 42. The transfection complex of claim 28, wherein the spacer comprises: i) a hydrophilic moiety and comprises about 6 to 30 carbon atoms; ii) a ployether; iii) a hydrophilic polymer; iv) a peptide of sequence APYKAWK (SEQ ID NO:505); or v) the GPI anchor peptide FTLTGLLGTLVTMGLLT (SEQ ID NO:504).
 43. (canceled)
 44. The transfection complex of claim 28, wherein the cationic peptide comprises repeats of lysine or arginine, or the cationic peptide comprises between 6-20 lysine residues (K6-K20) or between 6-20 arginine residues (R6-R20).
 45. (canceled)
 46. The transfection complex of claim 1, wherein the cell surface ligand is a sequence selected from the group consisting of SEQ ID NOs:202-500.
 47. The transfection complex of claim 1, wherein the transfection enhancer is: i) selected from the group consisting of a peptide or non-peptide transfection enhancer, a nuclear localization protein or peptide, a fusogenic peptide or non-peptide agent, a peptide or non-peptide endosomal release agent, a viral peptide or protein, a lysomolotropic agent, a cell penetration agent, a nuclear targeting agent, and a combination thereof; wherein the viral peptide or protein is optionally derived from a virus selected from the group consisting of an influenza virus, a vesicular stomatitis virus, an adenovirus, an alphavirus, a Semliki Forest Virus, a hepatitis virus, a herpes virus, an HIV virus, and a simian virus; or wherein the transfection enhancer is selected from the group consisting of insulin, a transferrin, a epidermal growth factor, a fibroblast growth factor, a cell targeting antibody or fragment from an antibody, a lactoferrin, a fibronectin, an adenovirus Penton base, Knob, a hexon protein, a vesicular stomatitis virus glycoprotein, a Semliki Forest Virus core protein, an influenza hemagglutinin, a hepatitis B core protein, an HIV Tat protein, a herpes simplex virus VP22 protein, a histone protein, an arginine rich cell permeability protein, a high mobility group protein, and invasin protein, an internalin protein, an endotoxin, a diptheria toxin, a shigella toxin, a melittin, a magainin, a gramicidin, a cecrophin, a defensin, a protegrin, a tachyplesin, a thionin, a indolicidin, a bactenecin, a drosomycin, an apidaecin, a cathelicidin, a bacteriacidal-Permability-increasing protein, a nisin, a buforin, and fragments thereof; or ii) the transfection enhancer comprises chloroquine, a lysosomotrophic compound or combinations thereof. 48-49. (canceled)
 50. The transfection complex of claim 47, wherein the nuclear localization protein or peptide is a sequence selected from the group consisting of SEQ ID NO:1 to SEQ ID NO:40.
 51. (canceled)
 52. The transfection complex of claim 1, further comprising: i) a biologically active agent; ii) one or more transfection helpers or targeting moieties in combination with the cell surface ligand, a) wherein the targeting moiety is optionally a molecule that targets a transfection complex to a specific tissue or cell type for targeted delivery of a biologically agent thereto, or b) wherein the targeting moiety is optionally a peptide, a modified peptide, an antibody, a modified antibody, a receptor molecule, a modified receptor molecule, a single or a double stranded nucleic acid molecule, a modified single or double stranded nucleic acid molecule, a peptide or nucleic acid aptamer, a modified peptide or nucleic acid aptamer, an organic molecule, and a polysaccharide; iii) a fusion agent, wherein the fusion agent is optionally a sequence selected from the group consisting of SEQ ID NOs:42-92; iv) a cell penetration agent, wherein the cell penetration agent is a sequence selected from the group consisting of SEQ ID NOs:74 and 93-96; v) a peptide or protein selected from the group consisting of a collagen, a fibronectin, a lamin, a veronectin, a cadherin, a nidogen, a fibrinogen, a elastin, a bone asialoprotein, a osteopontin, a tenascin-C, Avadin, insulin, a transferrin, a epidermal growth factor, a fibroblast growth factor, a cell targeting antibody, a lactoferrin, an adenovirus penton base, a knob protein, a hexon protein, a vesicular stomatitis virus glycoprotein, a Semliki Forest Virus core protein, an influenza hemaglutinin, a hepatitis B core protein, an HIV Tat protein, a herpes simplex virus VP22 protein, a histone protein, an arginine rich cell permeability protein, a high mobility group protein, invasin protein, internalin protein, an endotoxin, a non-toxic diptheria toxin, a non-toxic shigella toxin, a melittin, a magainin, a gramicidin, a cecrophin, a defensin, a protegrin, a tachyplesin, a thionin, a indolicidin, a bactenecin, a drosomycin, an apidaecin, a cathelicidin, a bacteriacidal-permability-increasing protein, a nisin, a buforin, a fragment thereof, and a sequence selected from the group consisting of SEQ ID NOs:150-197; or vi) at least one polyamine moiety selected from the group consisting of dense star dendrimers, PAMAM dendrimers, NH3 core dendrimers, ethylenediamine core dendrimers, dendrimers of generation 5 or higher, dendrimers with substituted groups, dendrimers having one or more amino acids, grafted dendrimers, activated dendrimers, polyethylenimine, and polyethylenimine conjugates, polycationic peptides such as polylysine, polyorinthine, polyhistidine, polyarginine. 53-61. (canceled)
 62. A pharmaceutical composition comprising the transfection complex of claim 1, and a pharmaceutically acceptable carrier.
 63. A method of transfecting a cell, the method comprising the steps of: obtaining a transfection complex of claim 1; and contacting a cell with the transfection complex.
 64. The method of claim 63, wherein the cell is selected from the group consisting of a primary cell culture, a passaged cell culture, suspension cell line and an attached cell line.
 65. The method of claim 63, wherein: i) the cell is a HeLa cell and the transfection complex comprises a peptide selected from the group consisting of SEQ ID NOs:107, 205, 216, 218, 219, 220, 224, 226, 229, 230, 234, 236, 236, 237, 238, 239, 256, 268, 323, 326, 327, 328, 332, 335, 336, 338, 341, 342, 343, 344, 345, 347, 348, 349, 350, 351, 352, 353, 354, 355, 357, 358, 359, 360, 361, 363, 365, 367, 369, 371, 373, 375, 377, 379, 381, 383, 450, 452, 454, and 503; ii) the cell is a HuVec cell and the transfection complex comprises a peptide selected from the group consisting of SEQ ID NOs:205, 216, 218, 219, 220, 224, 226, 229, 230, 234, 236, 236, 237, 238, 239, 256, 268, 323, 326, 327, 328, 332, 336, 338, 341, 342, 343, 344, 345, 347, 348, 349, 350, 351, 352, 353, 354, 355, 357, 358, 359, 360, 361, 363, 365, 367, 369, 371, 373, 375, 377, 379, 381, 383, 450, 452, 454, and 503; iii) the cell is an NL-1 iPS cell and the transfection complex comprises a peptide selected from the group consisting of SEQ ID NOs:107, 205, 216, 218, 219, 220, 224, 226, 229, 230, 234, 236, 236, 237, 238, 239, 256, 268, 323, 326, 327, 328, 332, 335, 336, 338, 341, 342, 343, 344, 345, 347, 348, 349, 350, 351, 352, 353, 354, 355, 357, 358, 359, 360, 361, 363, 365, 367, 369, 371, 373, 375, 377, 379, 381, 383, 450, 452, 454, and 503; iv) the cell is a C2C12 cell and the transfection complex comprises a peptide selected from the group consisting of SEQ ID NOs:205, 216, 218, 219, 220, 224, 226, 229, 230, 234, 236, 236, 237, 238, 239, 256, 268, 323, 326, 327, 328, 332, 335, 336, 338, 341, 342, 343, 344, 345, 347, 348, 350, 351, 352, 353, 354, 355, 357, 358, 359, 360, 361, 363, 365, 367, 369, 371, 373, 375, 377, 379, 381, 383, 450, 452, 454, 501, 502, and 503; v) the cell is a human fibroblast cell and the transfection complex comprises a peptide selected from the group consisting of SEQ ID NOs:205, 216, 218, 219, 220, 224, 226, 229, 230, 234, 236, 236, 237, 238, 239, 256, 268, 323, 326, 327, 328, 332, 335, 336, 338, 341, 342, 343, 344, 345, 347, 348, 349, 350, 351, 352, 353, 354, 355, 357, 358, 359, 360, 361, 363, 365, 367, 369, 371, 373, 375, 377, 379, 381, 383, 450, 452, 454, 501, and 503; vi) the cell is a Jurkat cell and the transfection complex comprises a peptide selected from the group consisting of SEQ ID NOs:205, 216, 218, 219, 220, 224, 226, 229, 230, 234, 236, 236, 237, 238, 239, 256, 268, 323, 326, 327, 328, 332, 335, 336, 338, 341, 342, 343, 344, 345, 347, 348, 349, 350, 351, 352, 353, 354, 355, 357, 358, 359, 360, 361, 363, 365, 367, 369, 371, 373, 375, 377, 379, 381, 383, 450, 452, 454, 501, and 503; vii) the cell is a rat cortical neuron cell and the transfection complex comprises a peptide selected from the group consisting of SEQ ID NOs: 220, 236, 238, 323, 327, 336, 338, 341, 343, 347, 348, 350, 351, 352, 354, 367, 369, 373, 375, 377, and 454; viii) the cell is a THP-1 cell and the transfection complex comprises a peptide selected from the group consisting of SEQ ID NOs:219, 229, 230, 239, 323, 328, 332, 341, 343, 350, 351, 357, 358, 375, 450, and 454; ix) the cell is a human skeletal muscle cell and the transfection complex comprises a peptide selected from the group consisting of SEQ ID NOs: 218, 219, 230, 328, 336, 344, 350, 351, 353, 355, 365, and
 375. 66-73. (canceled) 